A. Ilancheran | National University of Singapore (original) (raw)

Papers by A. Ilancheran

The Analyst, 2013

This study aims to evaluate the feasibility of applying high wavenumber (HW) confocal Raman spect... more This study aims to evaluate the feasibility of applying high wavenumber (HW) confocal Raman spectroscopy for non-invasive assessment of menopause-related hormonal changes in the cervix as well as for determining the effect of Vagifem(®) treatment on postmenopausal women with atrophic cervix. A rapid HW confocal Raman spectroscopy system coupled with a ball lens fiber-optic Raman probe was utilized for in vivo cervical tissue Raman measurements at 785 nm excitation. A total of 164 in vivo HW Raman spectra (premenopausal (n = 104), postmenopausal-prevagifem (n = 34), postmenopausal-postvagifem (n = 26)) were measured from the normal cervix of 26 patients undergoing colposcopy. We established the biochemical basis of premenopausal, postmenopausal-prevagifem and postmenopausal-postvagifem cervix using semiquantitative biomolecular modeling derived from Raman-active biochemicals (i.e., lipids, proteins and water) that play a critical role in HW Raman spectral changes associated with the menopausal process. The diagnostic algorithms developed based on partial least squares-discriminant analysis (PLS-DA) together with leave-one patient-out, cross-validation yielded the diagnostic sensitivities of 88.5%, 91.2% and 88.5%, and specificities of 91.7%, 90.8% and 99.3%, respectively, for non-invasive in vivo discrimination among premenopausal, postmenopausal-prevagifem and postmenopausal-postvagifem cervix. This work demonstrates for the first time that HW confocal Raman spectroscopy in conjunction with biomolecular modeling can be a powerful diagnostic tool for identifying hormone/menopause-related variations in the native squamous epithelium of normal cervix, as well as for assessing the effect of Vagifem treatment on postmenopausal atrophic cervix in vivo during clinical colposcopic inspections.

Journal of Biomedical Optics, 2013

Raman spectroscopy is a unique optical technique that can probe the changes of vibrational modes ... more Raman spectroscopy is a unique optical technique that can probe the changes of vibrational modes of biomolecules associated with tissue premalignant transformation. This study evaluates the clinical utility of confocal Raman spectroscopy over near-infrared (NIR) autofluorescence (AF) spectroscopy and composite NIR AF/Raman spectroscopy for improving early diagnosis of cervical precancer in vivo at colposcopy. A rapid NIR Raman system coupled with a ball-lens fiber-optic confocal Raman probe was utilized for in vivo NIR AF/Raman spectral measurements of the cervix. A total of 1240 in vivo Raman spectra [normal (n=993), dysplasia (n=247)] were acquired from 84 cervical patients. Principal components analysis (PCA) and linear discriminant analysis (LDA) together with a leave-one-patient-out, cross-validation method were used to extract the diagnostic information associated with distinctive spectroscopic modalities. The diagnostic ability of confocal Raman spectroscopy was evaluated using the PCA-LDA model developed from the significant principal components (PCs) [i.e., PC4, 0.0023%; PC5, 0.00095%; PC8, 0.00022%, (p<0.05)], representing the primary tissue Raman features (e.g., 854, 937, 1095, 1253, 1311, 1445, and 1654 cm(-1)). Confocal Raman spectroscopy coupled with PCA-LDA modeling yielded the diagnostic accuracy of 84.1% (a sensitivity of 81.0% and a specificity of 87.1%) for in vivo discrimination of dysplastic cervix. The receiver operating characteristic curves further confirmed that the best classification was achieved using confocal Raman spectroscopy compared to the composite NIR AF/Raman spectroscopy or NIR AF spectroscopy alone. This study illustrates that confocal Raman spectroscopy has great potential to improve early diagnosis of cervical precancer in vivo during clinical colposcopy.

Advanced Biomedical and Clinical Diagnostic Systems XI, 2013

Raman spectroscopy is a vibrational spectroscopic technique capable of optically probing the comp... more Raman spectroscopy is a vibrational spectroscopic technique capable of optically probing the compositional, conformational, and structural changes in the tissue associated with disease progression. The main goal of this work is to develop an integrated fingerprint (FP) and high wavenumber (HW) in vivo confocal Raman spectroscopy for simultaneous FP/HW tissue Raman spectral measurements. This work further explores the potential of integrated FP/HW Raman spectroscopy developed as a diagnostic tool for in vivo detection of cervical precancer. A total of 473 in vivo integrated FP/HW Raman spectra (340 normal and 133 precancer) were acquired from 35 patients within 1 s during clinical colposcopy. The major tissue Raman peaks are noticed around 854, 937, 1001, 1095, 1253, 1313, 1445, 1654, 2946 and 3400 cm -1 , related to the molecular changes (e.g., proteins, lipids, glycogen, nucleic acids, water, etc.) that accompany the dysplastic transformation of tissue. The FP (800 -1800 cm -1 ), HW (2800 -3800 cm -1 ) and the integrated FP/HW Raman spectra were analyzed using partial least squares-discriminant analysis (PLS-DA) together with the leave-one patient-out, cross-validation. The developed PLS-DA classification models and receiver operating characteristics (ROC) curves for the FP, HW and integrated FP/HW spectroscopy further discloses that the performance of integrated FP/HW Raman spectroscopy is superior to that of all others in discriminating the dysplastic cervix. The results of this work indicate that the co-contributions of underlying rich biochemical information revealed by the complementary spectral modalities (FP and HW Raman) can improve the in vivo early diagnosis of cervical precancer at clinical colposcopy

2008 Conference on Lasers and Electro-Optics, 2008

The purpose of this study is to explore the feasibility of combining near-infrared (NIR) autofluo... more The purpose of this study is to explore the feasibility of combining near-infrared (NIR) autofluorescence and Raman spectroscopy to enhance the in vivo detection of cervical intraepithelial neoplasia.

Archives of Gynecology and Obstetrics, 2011

To assess known cancer biomarkers CA-125, human tissue kallikreins KLK6 and KLK10, hemostatic mar... more To assess known cancer biomarkers CA-125, human tissue kallikreins KLK6 and KLK10, hemostatic markers and age with 5-year survival outcome from epithelial ovarian cancer. Forty-one benign cyst cohorts and 83 patients diagnosed with ovarian cancer were recruited. The following assays were performed: fibrinogen, vWF antigen, D: -dimer, ATIII activity, tPA, PAI-1, uPAR, KLK6, KLK10 and CA-125. Follow-up visits of cancer patients of more than 60 months were noted. Data between those who survived past 60 months and mortality from cancer were analyzed. Only 24 patients lived past 60 months, and 31 died (advanced stage n = 27). Those living past 60 months were significantly older and associated with similar pre-operative levels seen in benign cyst cohorts especially for KLK6, fibrinogen, vWF, AT levels despite upregulation of D: -dimer, CA-125 and KLK10. Ovarian cancer cohorts living past 60 months were younger than those who died within 12 months (n = 12). Mortality within 12 months was associated with older age, upregulation of KLK6, fibrinogen, D: -dimer, vWF, tPA antigen and reduced ATIII levels. Similarly, mortality within 36 months of disease showed older age with upregulation of CA-125, KLK6 D: -dimer vWF antigen and tPA antigen levels. Late stage cancer (III/IV) showed upregulated CA-125, KLK6, KLK10, D: -dimer and reduced AT compared to early stage cancer (I/II). The 5-year survival rate for early cancer was 80%, advanced 22.9% and overall 5-year survival rate was 43.6%. Older age together with the novel biomarkers studied and their association with adverse outcome from epithelial ovarian cancer was seen especially within 12 and 36 months of disease. Those who lived past 60 months of disease showed similar pre-operative levels seen in benign cyst cohorts despite elevated D: -dimer, CA125 and KLK 10. An enlarged study is needed to confirm these findings.

Asian Pacific journal of cancer prevention : APJCP, 2012

To assess the health and economic burden of human papillomavirus (HPV)-related diseases (cervical... more To assess the health and economic burden of human papillomavirus (HPV)-related diseases (cervical cancer, cervical intraepithelial neoplasia (CIN) 1/2/3, and genital warts) in Singapore over a period of 25 years beginning in 2008. Incidence-based modeling was used to estimate the incidence cases and associated economic burden, with the assumption that age-stratified incidence rates will remain the same throughout the period of 25 years. The incidence rates in 2008 were projected based on data obtained from the National Cancer Registry for cervical cancer, and from a combination of published data and hospital registry review for CIN1/2/3 and genital warts. The population growth rate was factored into the projection of incidence cases over time. Direct cost data per cervical cancer and per CIN1/2/3 case were obtained from the financial database of large local hospitals while cost data for genital warts were obtained from the National Skin Center; these costs were multiplied by the num...

Sexual Health, 2014

Background Genital warts (GW) are a common sexually transmissible infection (STI) among young adu... more Background Genital warts (GW) are a common sexually transmissible infection (STI) among young adults and are associated with poor quality of life (QoL). We investigated the functional and psychosocial effect of GW on Singaporean patients and evaluated for any variations in QoL between genders. Patients with GW completed a standard questionnaire containing the Short Form-36 (SF-36) health survey and the Cuestionario Específico para Condiloma Acuminado in a cross-sectional survey. QoL deficits were determined by comparing the SF-36 scores with local population norms. Variations in SF-36 (norm-based) scores among patients with different characteristics were examined using multiple linear regressions. All data analyses were performed for male and female patients separately. The mean age of male (n=100) and female patients (n=80) was 31 years. The typical patient profile was male, ethnic Chinese, single, tertiary education level and presenting with recurrent warts and a history of prior STIs. Compared with the general population, male patients had similar or better functioning and wellbeing, whereas female patients had lower levels of productivity, mental health and general health. Among male patients, individuals afflicted with their first episode of GW and currently with a partner had better QoL. In contrast, for females, tertiary education, older age and being a nonsmoker were positively associated with better QoL. Patients with GW have a significant psychosocial burden, with differences in certain aspects of QoL between genders. We hope that with active intervention, we will be able to mitigate the associated negative impact to QoL.

Gynecologic Oncology, 2010

Purpose. Diagnosis of cervical neoplasia hinges upon microscopic inspection of cervical samples. ... more Purpose. Diagnosis of cervical neoplasia hinges upon microscopic inspection of cervical samples. This has inherent operator-dependent variability. Testing for high-risk human papilloma virus (HPV) may help to triage patients with pre-invasive disease in determining clinical intervention and follow-up. However, HPV presence/absence does not reflect the cervical epithelial cell's molecular status. Epigenetic modifications, e.g. DNA methylation, have been observed in the early stages of neoplastic change, preceding gene mutations. Here, we assess the correlation between cytologic/histologic results and combined DNA methylation data of 5 genes in different grades of cervical dysplasia.

Best Practice & Research Clinical Obstetrics & Gynaecology, 2012

epithelial ovarian cancer fertility preservation congenital anomalies live births ovarian cryopre... more epithelial ovarian cancer fertility preservation congenital anomalies live births ovarian cryopreservation intraperitoneal chemotherapy

The Analyst, 2011

This study aimed to evaluate the clinical utility of applying near-infrared (NIR) Raman spectrosc... more This study aimed to evaluate the clinical utility of applying near-infrared (NIR) Raman spectroscopy and genetic algorithm-partial least squares-discriminant analysis (GA-PLS-DA) to identify biomolecular changes of cervical tissues associated with dysplastic transformation during colposcopic examination. A total of 105 in vivo Raman spectra were measured from 57 cervical sites (35 normal and 22 precancer sites) of 29 patients recruited, in which 65 spectra were from normal sites, while 40 spectra were from cervical precancerous lesions (i.e., 7 low-grade CIN and 33 high-grade CIN). The GA feature selection technique incorporated with PLS was utilized to study the significant biochemical Raman bands for differentiation between normal and precancer cervical tissues. The GA-PLS-DA algorithm with double cross-validation (dCV) identified seven diagnostically significant Raman bands in the ranges of 925related to proteins, nucleic acids and lipids in tissue, and yielded a diagnostic accuracy of 82.9% (sensitivity of 72.5% (29/40) and specificity of 89.2% (58/65)) for precancer detection. The results of this exploratory study suggest that Raman spectroscopy in conjunction with GA-PLS-DA and dCV methods has the potential to provide clinically significant discrimination between normal and precancer cervical tissues at the molecular level.

Best Practice & Research Clinical Obstetrics & Gynaecology, 2012

Cancer in pregnancy, fortunately, is uncommon. This is even more so for gynaecological cancer. Fe... more Cancer in pregnancy, fortunately, is uncommon. This is even more so for gynaecological cancer. Fertility preservation in gynaecological cancer is already a difficult issue, as the common gynaecological cancers affect organs intimately associated with conception and delivery. The presence of a viable pregnancy with gynaecological cancer presents tremendous challenges to the clinician, especially if the woman wants to conserve both her pregnancy and fertility. In this chapter, we address issues involved in such circumstances and suggest management decisions.

Analytical Chemistry, 2009

Raman spectroscopy is a vibrational spectroscopic technique capable of optically probing the biom... more Raman spectroscopy is a vibrational spectroscopic technique capable of optically probing the biomolecular changes associated with neoplastic transformation. The purpose of this study was to apply near-infrared (NIR) Raman spectroscopy in the high wavenumber (HW) region (2800-3700 cm(-1)) for in vivo detection of cervical dysplasia. A rapid-acquisition NIR Raman spectroscopy system associated with a ball-lens fiber-optic Raman probe was developed for in vivo spectroscopic measurements at 785 nm excitation. A total of 92 in vivo HW Raman spectra (46 normal, 46 dysplasia) were acquired from 46 patients with Pap smear abnormalities of the cervix. Significant difference in Raman intensities of prominent Raman bands at 2850 and 2885 cm(-1) (CH(2) stretching of lipids), 2940 cm(-1) (CH(3) stretching of proteins), and the broad Raman band of water (peaking at 3400 cm(-1) in the 3100-3700 cm(-1) range) were observed in normal and dysplasia cervical tissue. The diagnostic algorithms based on principal components analysis and linear discriminant analysis together with the leave-one-patient-out cross-validation method on in vivo HW Raman spectra yielded a diagnostic sensitivity of 93.5% and specificity of 97.8% for dysplasia tissue identification. This study demonstrates for the first time that HW Raman spectroscopy has the potential for the noninvasive, in vivo diagnosis and detection of precancer of the cervix.

The Lancet, 2014

Background Although adolescent girls are the main population for prophylactic human papillomaviru... more Background Although adolescent girls are the main population for prophylactic human papillomavirus (HPV) vaccines, adult women who remain at risk of cervical cancer can also be vaccinated. We report data from the interim analysis of the ongoing VIVIANE study, the aim of which is to assess the effi cacy, safety, and immunogenicity of the HPV 16/18 AS04-adjuvanted vaccine in adult women.

Annals of the Academy of Medicine, Singapore, 1998

Gestational trophoblastic diseases are a heterogenous group of conditions ranging from the benign... more Gestational trophoblastic diseases are a heterogenous group of conditions ranging from the benign hydatidiform mole to the malignant choriocarcinoma. Optimal therapy in this group of diseases rest in the correct diagnosis, assessing their risk for malignant behavior using prognostic scoring systems and administering appropriate treatment. Their rarity makes it imperative that these patients are treated in special centres by experts. Benign moles are treated surgically with evacuation of the uterus or hysterectomy. In malignant gestational trophoblastic disease, chemotherapy is the treatment of choice; single agent for non-metastatic and low-risk metastatic disease and combination chemotherapy for high-risk metastatic disease. Judicious use of surgery and radiotherapy in these cases will improve the survival rate. With appropriate treatment, the cure rates approach 100% in the low-risk group and 80% to 85% in the high risk group.

Optics in Health Care and Biomedical Optics III, 2007

Near-infrared (NIR) Raman spectroscopy has shown promise to detect cancer and precancer in human ... more Near-infrared (NIR) Raman spectroscopy has shown promise to detect cancer and precancer in human through measuring the biomolecular and biochemical changes of tissue associated with diseases transformation. Most of studies of NIR Raman spectroscopy on tissue diagnosis are concentrated on the so-called fingerprint region (800-1800 cm -1 ), there are only very limited work for tissue diagnosis using the high wavenumber (2800-3700 cm -1 ) spectral features. The purpose of this study is to explore the ability of NIR Raman spectroscopy in high wavenumber region for the in vivo detection of cervical precancer. A rapid NIR Raman spectroscopy system associated with a fiber-optic Raman probe was used for the in vivo spectroscopic measurements. Multivariate statistical techniques including principal components analysis (PCA) and linear discriminant analysis (LDA) were employed to develop the diagnostic algorithm based on the spectral data from 2800-3700 cm -1 . Classification result based on PCA-LDA showed that high wavenumber NIR Raman spectroscopy can achieve the diagnostic sensitivity of 93.5% and specificity of 95.7% for precancer classification.

The Analyst, 2013

This study aims to evaluate the feasibility of applying high wavenumber (HW) confocal Raman spect... more This study aims to evaluate the feasibility of applying high wavenumber (HW) confocal Raman spectroscopy for non-invasive assessment of menopause-related hormonal changes in the cervix as well as for determining the effect of Vagifem(®) treatment on postmenopausal women with atrophic cervix. A rapid HW confocal Raman spectroscopy system coupled with a ball lens fiber-optic Raman probe was utilized for in vivo cervical tissue Raman measurements at 785 nm excitation. A total of 164 in vivo HW Raman spectra (premenopausal (n = 104), postmenopausal-prevagifem (n = 34), postmenopausal-postvagifem (n = 26)) were measured from the normal cervix of 26 patients undergoing colposcopy. We established the biochemical basis of premenopausal, postmenopausal-prevagifem and postmenopausal-postvagifem cervix using semiquantitative biomolecular modeling derived from Raman-active biochemicals (i.e., lipids, proteins and water) that play a critical role in HW Raman spectral changes associated with the menopausal process. The diagnostic algorithms developed based on partial least squares-discriminant analysis (PLS-DA) together with leave-one patient-out, cross-validation yielded the diagnostic sensitivities of 88.5%, 91.2% and 88.5%, and specificities of 91.7%, 90.8% and 99.3%, respectively, for non-invasive in vivo discrimination among premenopausal, postmenopausal-prevagifem and postmenopausal-postvagifem cervix. This work demonstrates for the first time that HW confocal Raman spectroscopy in conjunction with biomolecular modeling can be a powerful diagnostic tool for identifying hormone/menopause-related variations in the native squamous epithelium of normal cervix, as well as for assessing the effect of Vagifem treatment on postmenopausal atrophic cervix in vivo during clinical colposcopic inspections.

Gynecologic Oncology, 2010

Purpose. Diagnosis of cervical neoplasia hinges upon microscopic inspection of cervical samples. ... more Purpose. Diagnosis of cervical neoplasia hinges upon microscopic inspection of cervical samples. This has inherent operator-dependent variability. Testing for high-risk human papilloma virus (HPV) may help to triage patients with pre-invasive disease in determining clinical intervention and follow-up. However, HPV presence/absence does not reflect the cervical epithelial cell's molecular status. Epigenetic modifications, e.g. DNA methylation, have been observed in the early stages of neoplastic change, preceding gene mutations. Here, we assess the correlation between cytologic/histologic results and combined DNA methylation data of 5 genes in different grades of cervical dysplasia.

Cancer, 1989

Multiple primary cancers account for only 0.38% of all cases in the Singapore Cancer Registry. Th... more Multiple primary cancers account for only 0.38% of all cases in the Singapore Cancer Registry. The close temporal association of nasopharyngeal carcinoma (NPC) in three Chinese women with uterine cervical adenocarcinoma was observed in our department within a 3-month period; one other case was extracted from the local literature. Although NPC is a common neoplasm in local Chinese women, uterine cervical adenocarcinomas comprise only 8% of cervical cancers locally. The close occurrence of these cancers does not seem to be related to the therapy used for cervical cancer and suggests that an association of the Epstein-Barr virus (EBV) with uterine cervical adenocarcinoma should be further investigated.

BJOG: An International Journal of Obstetrics and Gynaecology, 1988

Metastatic gestational trophoblastic disease poses problems in diagnosis and management and has a... more Metastatic gestational trophoblastic disease poses problems in diagnosis and management and has a poorer prognosis than the non-metastatic variant. The lung is the most common site of metastases. This paper reviews 97 patients with pulmonary metastasis developing after gestational trophoblastic disease who were seen at one centre over 26 years. Most patients had an antecedent molar pregnancy but an associated choriocarcinomatous lesion in the uterus was absent in the majority. In many patients the pulmonary lesion was asymptomatic. Whilst chemotherapy was the treatment of choice, selective thoracotomy in cases with solitary lung nodules reduced the treatment time and need for aggressive multi-drug combination regimens. The overall survival rate at 2 years after diagnosis was 65%. A higher mortality was found when the antecedent pregnancy ended at term, when the time interval between the preceding pregnancy and diagnosis of pulmonary metastases was greater than 1 year, when multiple pulmonary secondaries were present or when cerebral metastases occurred. The main causes of death were cerebral haemorrhage, respiratory failure and pulmonary embolism.

Analytical Chemistry, 2012

Raman spectroscopy is a vibrational spectroscopic technique capable of nondestructively probing e... more Raman spectroscopy is a vibrational spectroscopic technique capable of nondestructively probing endogenous biomolecules and their changes associated with dysplastic transformation in the tissue. The main objectives of this study are (i) to develop a simultaneous fingerprint (FP) and high-wavenumber (HW) confocal Raman spectroscopy and (ii) to investigate its diagnostic utility for improving in vivo diagnosis of cervical precancer (dysplasia). We have successfully developed an integrated FP/HW confocal Raman diagnostic system with a ball-lens Raman probe for simultaneous acquistion of FP/HW Raman signals of the cervix in vivo within 1 s. A total of 476 in vivo FP/HW Raman spectra (356 normal and 120 precancer) are acquired from 44 patients at clinical colposcopy. The distinctive Raman spectral differences between normal and dysplastic cervical tissue are observed at ∼854, 937, 1001, 1095, 1253, 1313, 1445, 1654, 2946, and 3400 cm −1 mainly related to proteins, lipids, glycogen, nucleic acids and water content in tissue. Multivariate diagnostic algorithms developed based on partial least-squares-discriminant analysis (PLS-DA) together with the leave-one-patient-out, cross-validation yield the diagnostic sensitivities of 84.2%, 76.7%, and 85.0%, respectively; specificities of 78.9%, 73.3%, and 81.7%, respectively; and overall diagnostic accuracies of 80.3%, 74.2%, and 82.6%, respectively, using FP, HW, and integrated FP/HW Raman spectroscopic techniques for in vivo diagnosis of cervical precancer. Receiver operating characteristic (ROC) analysis further confirms the best performance of the integrated FP/HW confocal Raman technique, compared to FP or HW Raman spectroscopy alone. This work demonstrates, for the first time, that the simultaneous FP/HW confocal Raman spectroscopy has the potential to be a clinically powerful tool for improving early diagnosis and detection of cervical precancer in vivo during clinical colposcopic examination.

The Analyst, 2013

This study aims to evaluate the feasibility of applying high wavenumber (HW) confocal Raman spect... more This study aims to evaluate the feasibility of applying high wavenumber (HW) confocal Raman spectroscopy for non-invasive assessment of menopause-related hormonal changes in the cervix as well as for determining the effect of Vagifem(®) treatment on postmenopausal women with atrophic cervix. A rapid HW confocal Raman spectroscopy system coupled with a ball lens fiber-optic Raman probe was utilized for in vivo cervical tissue Raman measurements at 785 nm excitation. A total of 164 in vivo HW Raman spectra (premenopausal (n = 104), postmenopausal-prevagifem (n = 34), postmenopausal-postvagifem (n = 26)) were measured from the normal cervix of 26 patients undergoing colposcopy. We established the biochemical basis of premenopausal, postmenopausal-prevagifem and postmenopausal-postvagifem cervix using semiquantitative biomolecular modeling derived from Raman-active biochemicals (i.e., lipids, proteins and water) that play a critical role in HW Raman spectral changes associated with the menopausal process. The diagnostic algorithms developed based on partial least squares-discriminant analysis (PLS-DA) together with leave-one patient-out, cross-validation yielded the diagnostic sensitivities of 88.5%, 91.2% and 88.5%, and specificities of 91.7%, 90.8% and 99.3%, respectively, for non-invasive in vivo discrimination among premenopausal, postmenopausal-prevagifem and postmenopausal-postvagifem cervix. This work demonstrates for the first time that HW confocal Raman spectroscopy in conjunction with biomolecular modeling can be a powerful diagnostic tool for identifying hormone/menopause-related variations in the native squamous epithelium of normal cervix, as well as for assessing the effect of Vagifem treatment on postmenopausal atrophic cervix in vivo during clinical colposcopic inspections.

Journal of Biomedical Optics, 2013

Raman spectroscopy is a unique optical technique that can probe the changes of vibrational modes ... more Raman spectroscopy is a unique optical technique that can probe the changes of vibrational modes of biomolecules associated with tissue premalignant transformation. This study evaluates the clinical utility of confocal Raman spectroscopy over near-infrared (NIR) autofluorescence (AF) spectroscopy and composite NIR AF/Raman spectroscopy for improving early diagnosis of cervical precancer in vivo at colposcopy. A rapid NIR Raman system coupled with a ball-lens fiber-optic confocal Raman probe was utilized for in vivo NIR AF/Raman spectral measurements of the cervix. A total of 1240 in vivo Raman spectra [normal (n=993), dysplasia (n=247)] were acquired from 84 cervical patients. Principal components analysis (PCA) and linear discriminant analysis (LDA) together with a leave-one-patient-out, cross-validation method were used to extract the diagnostic information associated with distinctive spectroscopic modalities. The diagnostic ability of confocal Raman spectroscopy was evaluated using the PCA-LDA model developed from the significant principal components (PCs) [i.e., PC4, 0.0023%; PC5, 0.00095%; PC8, 0.00022%, (p<0.05)], representing the primary tissue Raman features (e.g., 854, 937, 1095, 1253, 1311, 1445, and 1654 cm(-1)). Confocal Raman spectroscopy coupled with PCA-LDA modeling yielded the diagnostic accuracy of 84.1% (a sensitivity of 81.0% and a specificity of 87.1%) for in vivo discrimination of dysplastic cervix. The receiver operating characteristic curves further confirmed that the best classification was achieved using confocal Raman spectroscopy compared to the composite NIR AF/Raman spectroscopy or NIR AF spectroscopy alone. This study illustrates that confocal Raman spectroscopy has great potential to improve early diagnosis of cervical precancer in vivo during clinical colposcopy.

Advanced Biomedical and Clinical Diagnostic Systems XI, 2013

Raman spectroscopy is a vibrational spectroscopic technique capable of optically probing the comp... more Raman spectroscopy is a vibrational spectroscopic technique capable of optically probing the compositional, conformational, and structural changes in the tissue associated with disease progression. The main goal of this work is to develop an integrated fingerprint (FP) and high wavenumber (HW) in vivo confocal Raman spectroscopy for simultaneous FP/HW tissue Raman spectral measurements. This work further explores the potential of integrated FP/HW Raman spectroscopy developed as a diagnostic tool for in vivo detection of cervical precancer. A total of 473 in vivo integrated FP/HW Raman spectra (340 normal and 133 precancer) were acquired from 35 patients within 1 s during clinical colposcopy. The major tissue Raman peaks are noticed around 854, 937, 1001, 1095, 1253, 1313, 1445, 1654, 2946 and 3400 cm -1 , related to the molecular changes (e.g., proteins, lipids, glycogen, nucleic acids, water, etc.) that accompany the dysplastic transformation of tissue. The FP (800 -1800 cm -1 ), HW (2800 -3800 cm -1 ) and the integrated FP/HW Raman spectra were analyzed using partial least squares-discriminant analysis (PLS-DA) together with the leave-one patient-out, cross-validation. The developed PLS-DA classification models and receiver operating characteristics (ROC) curves for the FP, HW and integrated FP/HW spectroscopy further discloses that the performance of integrated FP/HW Raman spectroscopy is superior to that of all others in discriminating the dysplastic cervix. The results of this work indicate that the co-contributions of underlying rich biochemical information revealed by the complementary spectral modalities (FP and HW Raman) can improve the in vivo early diagnosis of cervical precancer at clinical colposcopy

2008 Conference on Lasers and Electro-Optics, 2008

The purpose of this study is to explore the feasibility of combining near-infrared (NIR) autofluo... more The purpose of this study is to explore the feasibility of combining near-infrared (NIR) autofluorescence and Raman spectroscopy to enhance the in vivo detection of cervical intraepithelial neoplasia.

Archives of Gynecology and Obstetrics, 2011

To assess known cancer biomarkers CA-125, human tissue kallikreins KLK6 and KLK10, hemostatic mar... more To assess known cancer biomarkers CA-125, human tissue kallikreins KLK6 and KLK10, hemostatic markers and age with 5-year survival outcome from epithelial ovarian cancer. Forty-one benign cyst cohorts and 83 patients diagnosed with ovarian cancer were recruited. The following assays were performed: fibrinogen, vWF antigen, D: -dimer, ATIII activity, tPA, PAI-1, uPAR, KLK6, KLK10 and CA-125. Follow-up visits of cancer patients of more than 60 months were noted. Data between those who survived past 60 months and mortality from cancer were analyzed. Only 24 patients lived past 60 months, and 31 died (advanced stage n = 27). Those living past 60 months were significantly older and associated with similar pre-operative levels seen in benign cyst cohorts especially for KLK6, fibrinogen, vWF, AT levels despite upregulation of D: -dimer, CA-125 and KLK10. Ovarian cancer cohorts living past 60 months were younger than those who died within 12 months (n = 12). Mortality within 12 months was associated with older age, upregulation of KLK6, fibrinogen, D: -dimer, vWF, tPA antigen and reduced ATIII levels. Similarly, mortality within 36 months of disease showed older age with upregulation of CA-125, KLK6 D: -dimer vWF antigen and tPA antigen levels. Late stage cancer (III/IV) showed upregulated CA-125, KLK6, KLK10, D: -dimer and reduced AT compared to early stage cancer (I/II). The 5-year survival rate for early cancer was 80%, advanced 22.9% and overall 5-year survival rate was 43.6%. Older age together with the novel biomarkers studied and their association with adverse outcome from epithelial ovarian cancer was seen especially within 12 and 36 months of disease. Those who lived past 60 months of disease showed similar pre-operative levels seen in benign cyst cohorts despite elevated D: -dimer, CA125 and KLK 10. An enlarged study is needed to confirm these findings.

Asian Pacific journal of cancer prevention : APJCP, 2012

To assess the health and economic burden of human papillomavirus (HPV)-related diseases (cervical... more To assess the health and economic burden of human papillomavirus (HPV)-related diseases (cervical cancer, cervical intraepithelial neoplasia (CIN) 1/2/3, and genital warts) in Singapore over a period of 25 years beginning in 2008. Incidence-based modeling was used to estimate the incidence cases and associated economic burden, with the assumption that age-stratified incidence rates will remain the same throughout the period of 25 years. The incidence rates in 2008 were projected based on data obtained from the National Cancer Registry for cervical cancer, and from a combination of published data and hospital registry review for CIN1/2/3 and genital warts. The population growth rate was factored into the projection of incidence cases over time. Direct cost data per cervical cancer and per CIN1/2/3 case were obtained from the financial database of large local hospitals while cost data for genital warts were obtained from the National Skin Center; these costs were multiplied by the num...

Sexual Health, 2014

Background Genital warts (GW) are a common sexually transmissible infection (STI) among young adu... more Background Genital warts (GW) are a common sexually transmissible infection (STI) among young adults and are associated with poor quality of life (QoL). We investigated the functional and psychosocial effect of GW on Singaporean patients and evaluated for any variations in QoL between genders. Patients with GW completed a standard questionnaire containing the Short Form-36 (SF-36) health survey and the Cuestionario Específico para Condiloma Acuminado in a cross-sectional survey. QoL deficits were determined by comparing the SF-36 scores with local population norms. Variations in SF-36 (norm-based) scores among patients with different characteristics were examined using multiple linear regressions. All data analyses were performed for male and female patients separately. The mean age of male (n=100) and female patients (n=80) was 31 years. The typical patient profile was male, ethnic Chinese, single, tertiary education level and presenting with recurrent warts and a history of prior STIs. Compared with the general population, male patients had similar or better functioning and wellbeing, whereas female patients had lower levels of productivity, mental health and general health. Among male patients, individuals afflicted with their first episode of GW and currently with a partner had better QoL. In contrast, for females, tertiary education, older age and being a nonsmoker were positively associated with better QoL. Patients with GW have a significant psychosocial burden, with differences in certain aspects of QoL between genders. We hope that with active intervention, we will be able to mitigate the associated negative impact to QoL.

Gynecologic Oncology, 2010

Purpose. Diagnosis of cervical neoplasia hinges upon microscopic inspection of cervical samples. ... more Purpose. Diagnosis of cervical neoplasia hinges upon microscopic inspection of cervical samples. This has inherent operator-dependent variability. Testing for high-risk human papilloma virus (HPV) may help to triage patients with pre-invasive disease in determining clinical intervention and follow-up. However, HPV presence/absence does not reflect the cervical epithelial cell's molecular status. Epigenetic modifications, e.g. DNA methylation, have been observed in the early stages of neoplastic change, preceding gene mutations. Here, we assess the correlation between cytologic/histologic results and combined DNA methylation data of 5 genes in different grades of cervical dysplasia.

Best Practice & Research Clinical Obstetrics & Gynaecology, 2012

epithelial ovarian cancer fertility preservation congenital anomalies live births ovarian cryopre... more epithelial ovarian cancer fertility preservation congenital anomalies live births ovarian cryopreservation intraperitoneal chemotherapy

The Analyst, 2011

This study aimed to evaluate the clinical utility of applying near-infrared (NIR) Raman spectrosc... more This study aimed to evaluate the clinical utility of applying near-infrared (NIR) Raman spectroscopy and genetic algorithm-partial least squares-discriminant analysis (GA-PLS-DA) to identify biomolecular changes of cervical tissues associated with dysplastic transformation during colposcopic examination. A total of 105 in vivo Raman spectra were measured from 57 cervical sites (35 normal and 22 precancer sites) of 29 patients recruited, in which 65 spectra were from normal sites, while 40 spectra were from cervical precancerous lesions (i.e., 7 low-grade CIN and 33 high-grade CIN). The GA feature selection technique incorporated with PLS was utilized to study the significant biochemical Raman bands for differentiation between normal and precancer cervical tissues. The GA-PLS-DA algorithm with double cross-validation (dCV) identified seven diagnostically significant Raman bands in the ranges of 925related to proteins, nucleic acids and lipids in tissue, and yielded a diagnostic accuracy of 82.9% (sensitivity of 72.5% (29/40) and specificity of 89.2% (58/65)) for precancer detection. The results of this exploratory study suggest that Raman spectroscopy in conjunction with GA-PLS-DA and dCV methods has the potential to provide clinically significant discrimination between normal and precancer cervical tissues at the molecular level.

Best Practice & Research Clinical Obstetrics & Gynaecology, 2012

Cancer in pregnancy, fortunately, is uncommon. This is even more so for gynaecological cancer. Fe... more Cancer in pregnancy, fortunately, is uncommon. This is even more so for gynaecological cancer. Fertility preservation in gynaecological cancer is already a difficult issue, as the common gynaecological cancers affect organs intimately associated with conception and delivery. The presence of a viable pregnancy with gynaecological cancer presents tremendous challenges to the clinician, especially if the woman wants to conserve both her pregnancy and fertility. In this chapter, we address issues involved in such circumstances and suggest management decisions.

Analytical Chemistry, 2009

Raman spectroscopy is a vibrational spectroscopic technique capable of optically probing the biom... more Raman spectroscopy is a vibrational spectroscopic technique capable of optically probing the biomolecular changes associated with neoplastic transformation. The purpose of this study was to apply near-infrared (NIR) Raman spectroscopy in the high wavenumber (HW) region (2800-3700 cm(-1)) for in vivo detection of cervical dysplasia. A rapid-acquisition NIR Raman spectroscopy system associated with a ball-lens fiber-optic Raman probe was developed for in vivo spectroscopic measurements at 785 nm excitation. A total of 92 in vivo HW Raman spectra (46 normal, 46 dysplasia) were acquired from 46 patients with Pap smear abnormalities of the cervix. Significant difference in Raman intensities of prominent Raman bands at 2850 and 2885 cm(-1) (CH(2) stretching of lipids), 2940 cm(-1) (CH(3) stretching of proteins), and the broad Raman band of water (peaking at 3400 cm(-1) in the 3100-3700 cm(-1) range) were observed in normal and dysplasia cervical tissue. The diagnostic algorithms based on principal components analysis and linear discriminant analysis together with the leave-one-patient-out cross-validation method on in vivo HW Raman spectra yielded a diagnostic sensitivity of 93.5% and specificity of 97.8% for dysplasia tissue identification. This study demonstrates for the first time that HW Raman spectroscopy has the potential for the noninvasive, in vivo diagnosis and detection of precancer of the cervix.

The Lancet, 2014

Background Although adolescent girls are the main population for prophylactic human papillomaviru... more Background Although adolescent girls are the main population for prophylactic human papillomavirus (HPV) vaccines, adult women who remain at risk of cervical cancer can also be vaccinated. We report data from the interim analysis of the ongoing VIVIANE study, the aim of which is to assess the effi cacy, safety, and immunogenicity of the HPV 16/18 AS04-adjuvanted vaccine in adult women.

Annals of the Academy of Medicine, Singapore, 1998

Gestational trophoblastic diseases are a heterogenous group of conditions ranging from the benign... more Gestational trophoblastic diseases are a heterogenous group of conditions ranging from the benign hydatidiform mole to the malignant choriocarcinoma. Optimal therapy in this group of diseases rest in the correct diagnosis, assessing their risk for malignant behavior using prognostic scoring systems and administering appropriate treatment. Their rarity makes it imperative that these patients are treated in special centres by experts. Benign moles are treated surgically with evacuation of the uterus or hysterectomy. In malignant gestational trophoblastic disease, chemotherapy is the treatment of choice; single agent for non-metastatic and low-risk metastatic disease and combination chemotherapy for high-risk metastatic disease. Judicious use of surgery and radiotherapy in these cases will improve the survival rate. With appropriate treatment, the cure rates approach 100% in the low-risk group and 80% to 85% in the high risk group.

Optics in Health Care and Biomedical Optics III, 2007

Near-infrared (NIR) Raman spectroscopy has shown promise to detect cancer and precancer in human ... more Near-infrared (NIR) Raman spectroscopy has shown promise to detect cancer and precancer in human through measuring the biomolecular and biochemical changes of tissue associated with diseases transformation. Most of studies of NIR Raman spectroscopy on tissue diagnosis are concentrated on the so-called fingerprint region (800-1800 cm -1 ), there are only very limited work for tissue diagnosis using the high wavenumber (2800-3700 cm -1 ) spectral features. The purpose of this study is to explore the ability of NIR Raman spectroscopy in high wavenumber region for the in vivo detection of cervical precancer. A rapid NIR Raman spectroscopy system associated with a fiber-optic Raman probe was used for the in vivo spectroscopic measurements. Multivariate statistical techniques including principal components analysis (PCA) and linear discriminant analysis (LDA) were employed to develop the diagnostic algorithm based on the spectral data from 2800-3700 cm -1 . Classification result based on PCA-LDA showed that high wavenumber NIR Raman spectroscopy can achieve the diagnostic sensitivity of 93.5% and specificity of 95.7% for precancer classification.

The Analyst, 2013

This study aims to evaluate the feasibility of applying high wavenumber (HW) confocal Raman spect... more This study aims to evaluate the feasibility of applying high wavenumber (HW) confocal Raman spectroscopy for non-invasive assessment of menopause-related hormonal changes in the cervix as well as for determining the effect of Vagifem(®) treatment on postmenopausal women with atrophic cervix. A rapid HW confocal Raman spectroscopy system coupled with a ball lens fiber-optic Raman probe was utilized for in vivo cervical tissue Raman measurements at 785 nm excitation. A total of 164 in vivo HW Raman spectra (premenopausal (n = 104), postmenopausal-prevagifem (n = 34), postmenopausal-postvagifem (n = 26)) were measured from the normal cervix of 26 patients undergoing colposcopy. We established the biochemical basis of premenopausal, postmenopausal-prevagifem and postmenopausal-postvagifem cervix using semiquantitative biomolecular modeling derived from Raman-active biochemicals (i.e., lipids, proteins and water) that play a critical role in HW Raman spectral changes associated with the menopausal process. The diagnostic algorithms developed based on partial least squares-discriminant analysis (PLS-DA) together with leave-one patient-out, cross-validation yielded the diagnostic sensitivities of 88.5%, 91.2% and 88.5%, and specificities of 91.7%, 90.8% and 99.3%, respectively, for non-invasive in vivo discrimination among premenopausal, postmenopausal-prevagifem and postmenopausal-postvagifem cervix. This work demonstrates for the first time that HW confocal Raman spectroscopy in conjunction with biomolecular modeling can be a powerful diagnostic tool for identifying hormone/menopause-related variations in the native squamous epithelium of normal cervix, as well as for assessing the effect of Vagifem treatment on postmenopausal atrophic cervix in vivo during clinical colposcopic inspections.

Gynecologic Oncology, 2010

Purpose. Diagnosis of cervical neoplasia hinges upon microscopic inspection of cervical samples. ... more Purpose. Diagnosis of cervical neoplasia hinges upon microscopic inspection of cervical samples. This has inherent operator-dependent variability. Testing for high-risk human papilloma virus (HPV) may help to triage patients with pre-invasive disease in determining clinical intervention and follow-up. However, HPV presence/absence does not reflect the cervical epithelial cell's molecular status. Epigenetic modifications, e.g. DNA methylation, have been observed in the early stages of neoplastic change, preceding gene mutations. Here, we assess the correlation between cytologic/histologic results and combined DNA methylation data of 5 genes in different grades of cervical dysplasia.

Cancer, 1989

Multiple primary cancers account for only 0.38% of all cases in the Singapore Cancer Registry. Th... more Multiple primary cancers account for only 0.38% of all cases in the Singapore Cancer Registry. The close temporal association of nasopharyngeal carcinoma (NPC) in three Chinese women with uterine cervical adenocarcinoma was observed in our department within a 3-month period; one other case was extracted from the local literature. Although NPC is a common neoplasm in local Chinese women, uterine cervical adenocarcinomas comprise only 8% of cervical cancers locally. The close occurrence of these cancers does not seem to be related to the therapy used for cervical cancer and suggests that an association of the Epstein-Barr virus (EBV) with uterine cervical adenocarcinoma should be further investigated.

BJOG: An International Journal of Obstetrics and Gynaecology, 1988

Metastatic gestational trophoblastic disease poses problems in diagnosis and management and has a... more Metastatic gestational trophoblastic disease poses problems in diagnosis and management and has a poorer prognosis than the non-metastatic variant. The lung is the most common site of metastases. This paper reviews 97 patients with pulmonary metastasis developing after gestational trophoblastic disease who were seen at one centre over 26 years. Most patients had an antecedent molar pregnancy but an associated choriocarcinomatous lesion in the uterus was absent in the majority. In many patients the pulmonary lesion was asymptomatic. Whilst chemotherapy was the treatment of choice, selective thoracotomy in cases with solitary lung nodules reduced the treatment time and need for aggressive multi-drug combination regimens. The overall survival rate at 2 years after diagnosis was 65%. A higher mortality was found when the antecedent pregnancy ended at term, when the time interval between the preceding pregnancy and diagnosis of pulmonary metastases was greater than 1 year, when multiple pulmonary secondaries were present or when cerebral metastases occurred. The main causes of death were cerebral haemorrhage, respiratory failure and pulmonary embolism.

Analytical Chemistry, 2012

Raman spectroscopy is a vibrational spectroscopic technique capable of nondestructively probing e... more Raman spectroscopy is a vibrational spectroscopic technique capable of nondestructively probing endogenous biomolecules and their changes associated with dysplastic transformation in the tissue. The main objectives of this study are (i) to develop a simultaneous fingerprint (FP) and high-wavenumber (HW) confocal Raman spectroscopy and (ii) to investigate its diagnostic utility for improving in vivo diagnosis of cervical precancer (dysplasia). We have successfully developed an integrated FP/HW confocal Raman diagnostic system with a ball-lens Raman probe for simultaneous acquistion of FP/HW Raman signals of the cervix in vivo within 1 s. A total of 476 in vivo FP/HW Raman spectra (356 normal and 120 precancer) are acquired from 44 patients at clinical colposcopy. The distinctive Raman spectral differences between normal and dysplastic cervical tissue are observed at ∼854, 937, 1001, 1095, 1253, 1313, 1445, 1654, 2946, and 3400 cm −1 mainly related to proteins, lipids, glycogen, nucleic acids and water content in tissue. Multivariate diagnostic algorithms developed based on partial least-squares-discriminant analysis (PLS-DA) together with the leave-one-patient-out, cross-validation yield the diagnostic sensitivities of 84.2%, 76.7%, and 85.0%, respectively; specificities of 78.9%, 73.3%, and 81.7%, respectively; and overall diagnostic accuracies of 80.3%, 74.2%, and 82.6%, respectively, using FP, HW, and integrated FP/HW Raman spectroscopic techniques for in vivo diagnosis of cervical precancer. Receiver operating characteristic (ROC) analysis further confirms the best performance of the integrated FP/HW confocal Raman technique, compared to FP or HW Raman spectroscopy alone. This work demonstrates, for the first time, that the simultaneous FP/HW confocal Raman spectroscopy has the potential to be a clinically powerful tool for improving early diagnosis and detection of cervical precancer in vivo during clinical colposcopic examination.