Alexander Vlantis - Academia.edu (original) (raw)

Papers by Alexander Vlantis

Scientific Reports

The aim of this study was to evaluate the impact of lymph node status from neck dissection pathol... more The aim of this study was to evaluate the impact of lymph node status from neck dissection pathological specimens on the survival for isolated regional nodal recurrence or persistence after primary treatment of nasopharyngeal carcinoma. Through a retrospective cohort study performed in an academic tertiary referral hospital in Hong Kong. Forty-six patients who underwent a salvage neck dissection between June 2001 and January 2013 for isolated regionally recurrent or persistent nasopharyngeal carcinoma was performed. Informed consent was waived for this retrospective study by The Joint CUHK-NTEC CREC. In the study forty-six patients had a salvage neck dissection for nodal failure with a mean age of 53 and 74% (34) were male. With a mean follow-up of 45.3 months, Overall survival, disease specific survival, loco-regional recurrence free survival, and regional recurrence free survival were 56.5%, 73.9%, 87.0%, and 91.3% respectively. For both univariate and multivariate analysis, patie...

European Radiology

ObjectivesMRI can detect early-stage nasopharyngeal carcinoma (NPC), but the detection is more ch... more ObjectivesMRI can detect early-stage nasopharyngeal carcinoma (NPC), but the detection is more challenging in early-stage NPCs because they must be distinguished from benign hyperplasia in the nasopharynx. This study aimed to determine whether intravoxel incoherent motion diffusion-weighted imaging (IVIM DWI) MRI could distinguish between these two entities.MethodsThirty-four subjects with early-stage NPC and 30 subjects with benign hyperplasia prospectively underwent IVIM DWI. The mean pure diffusion coefficient (D), pseudo-diffusion coefficient (D*), perfusion fraction (f) and apparent diffusion coefficient (ADC) values were calculated for all subjects and compared between the 2 groups using Student’s t test. Receiver operating characteristics with the area under the curve (AUC) was used to identify the optimal threshold for all significant parameters, and the corresponding diagnostic performance was calculated. A p value of < 0.05 was considered statistically significant.ResultsCompared with benign hyperplasia, early-stage NPC exhibited a significantly lower D mean (0.64 ± 0.06 vs 0.87 ± 0.11 × 10−3 mm2/s), ADC0–1000 mean (0.77 ± 0.08 vs 1.00 ± 0.13 × 10−3 mm2/s), ADC300–1000 (0.63 ± 0.05 vs 0.86 ± 0.10 × 10−3 mm2/s) and a higher D* mean (32.66 ± 4.79 vs 21.96 ± 5.21 × 10−3 mm2/s) (all p < 0.001). No significant difference in the f mean was observed between the two groups (p = 0.216). The D and ADC300–1000 mean had the highest AUC of 0.985 and 0.988, respectively, and the D mean of < 0.75 × 10−3 mm2/s yielded the highest sensitivity, specificity and accuracy (100%, 93.3% and 96.9%, respectively) in distinguishing early-stage NPC from benign hyperplasia.ConclusionDWI has potential to distinguish early-stage NPC from benign hyperplasia and D and ADC300–1000 mean were the most promising parameters.Key Points• Diffusion-weighted imaging has potential to distinguish early-stage nasopharyngeal carcinoma from benign hyperplasia in the nasopharynx.• The pure diffusion coefficient, pseudo-diffusion coefficient from intravoxel incoherent motion model and apparent diffusion coefficient from conventional diffusion-weighted imaging were significant parameters for distinguishing these two entities in the nasopharynx.• The pure diffusion coefficient, followed by apparent diffusion coefficient, may be the most promising parameters to be used in screening studies to help detect early-stage nasopharyngeal carcinoma.

Journal of neurological surgery. Part B, Skull base, 2018

To describe the first experience with a free vastus lateralis muscle-only flap to be used to cov... more To describe the first experience with a free vastus lateralis muscle-only flap to be used to cover and protect the exposed skull base and carotid artery from radiotherapy-induced skull base osteoradionecrosis (ORN). Retrospective review of a case series. Tertiary academic medical center. Post treatment nasopharyngeal carcinoma patients with skull base ORN. Coverage of the internal carotid artery (ICA). Four patients underwent the procedure. Following the procedure, all patients were documented to have adequate viable soft tissue covering their ICA. Topical nasal steroids were prescribed to all patients as florid granulation tissue was noted to occur overlying the muscle flap in the early postoperative period. There were no flap failures. All patients noted an improvement in speech, cacosmia, and nasal crusting. No significant epistaxis occurred following surgery. Choanal stenosis was noted in three patients. For skull base ORN resulting from the treatment of nasopharyngeal ca...

F1000Research, 2018

Narrow band imaging (NBI), an endoscopic technique featuring Background an augmented definition o... more Narrow band imaging (NBI), an endoscopic technique featuring Background an augmented definition of microvasculature and mucosal patterns. NBI is increasingly advocated as a tool to characterize neoplasia and intestinal metaplasia in endoscopic standards, such as for colorectal polyps and tumors. Recently NBI has also been studied in the detection of Nasopharyngeal Carcinoma (NPC). Here we aimed to assess the diagnostic utility of NBI for the diagnosis of NPC. A meta-analysis of studies comparing narrow-band imaging and Methods: white light endoscopy in the diagnosis of primary nasopharyngeal carcinoma was performed. The review process involved two independent investigators. The databases used were MEDLINE, PubMed, the Cochrane library, Embase, and the Web of Science. Statistical analysis was performed with OpenMetaAnalyst, MetaDiSc version 1.4, and Medcalc version 17.9.7. : Five studies including 2480 patients were included. The sensitivity Results and specificity for narrow-band imaging were 0.90 (0.73-0.97) and 0.95 (0.81-0.99) respectively. The positive likelihood ratio and negative likelihood ratio were 18.82 (0.31-82.1) and 0.08 (0.02-0.31). For white light endoscopy, the sensitivity and specificity were 0.77 (0.58-0.89) and 0.91 (0.79-0.96). The positive likelihood ratio was 7.61 (3.61-16.04), and the negative likelihood ratio was 0.21 (0.11-0.39). The odds ratio for detection rates between narrow-band imaging and white light endoscopy was 4.29 (0.56-33.03, p = 0.16). Area under the curve for narrow-band imaging was 0.98 (SE: 0.02), and for white light it was 0.93 (SE: 0.03). There was no significant difference in the receiver operating characteristic curves between the two modalities (p = 0.14). : Narrow-band imaging showed a higher sensitivity and positive Conclusion likelihood ratio for the diagnosis of nasopharyngeal carcinoma. However, there was no significant difference in detection rates compared to white light endoscopy. Further investigation with a uniform diagnostic criteria and terminology is needed for narrow-band imaging in the diagnosis of nasopharyngeal carcinoma.

The Laryngoscope, Jan 12, 2018

To assess interobserver agreement and intraobserver reproducibility when assessing the nasopharyn... more To assess interobserver agreement and intraobserver reproducibility when assessing the nasopharynx for malignancy under white light and narrow band imaging endoscopy because the decision to biopsy hinges on the examiner's perceived chance of malignancy. An interobserver and intraobserver agreement study utilizing white light and narrow band endoscopic images of the nasopharynx. The setting was an academic referral hospital. Participants were 156 adults with suspected nasopharyngeal carcinoma who underwent white light and narrow band imaging endoscopy and biopsy. Images of the nasopharynges were subsequently scored for malignancy by four otolaryngologists. The nasopharynx was scored on 4-point scales under white light and narrow band imaging endoscopy for the likelihood of malignancy or abnormality, respectively. Intraclass correlation coefficients for intraobserver agreement for nasopharyngeal malignancy for four observers under white light were 0.86, 0.89, 0.79 and 0.88 (mean 0...

Molecular therapy : the journal of the American Society of Gene Therapy, Jan 5, 2018

Thyroid cancer is rapidly increasing in incidence worldwide. Although most thyroid cancer can be ... more Thyroid cancer is rapidly increasing in incidence worldwide. Although most thyroid cancer can be cured with surgery, radioactive iodine, and/or chemotherapy, thyroid cancers still recur and may become chemoresistant. Autophagy is a complex self-degradative process that plays a dual role in cancer development and progression. In this study, we found that miR-125b was downregulated in tissue samples of thyroid cancer as well as in thyroid cancer cell lines, and the expression of Foxp3 was upregulated. Further, we demonstrated that miR-125b could directly act on Foxp3 by binding to its 3' UTR and inhibit the expression of Foxp3. A negative relationship between miR-125b and Foxp3 was thus revealed. Overexpression of miR-125b markedly sensitized thyroid cancer cells to cisplatin treatment by inducing autophagy through an Atg7 pathway in vitro and in vivo. Taken together, our findings demonstrate a novel mechanism by which miR-125b has the potential to negatively regulate Foxp3 to pro...

Surgical Practice, 2017

The aim of the present study was to determine the accuracy of diagnostic sialendoscopy in patient... more The aim of the present study was to determine the accuracy of diagnostic sialendoscopy in patients with suspected obstructive salivary duct disease referenced to current imaging modalities.

International forum of allergy & rhinology, Apr 16, 2016

To critically evaluate the use of endoscopic nasopharyngectomy in the treatment of recurrent naso... more To critically evaluate the use of endoscopic nasopharyngectomy in the treatment of recurrent nasopharyngeal carcinoma (NPC) through a case series, systematic literature review, and pooled analysis. A case series of 18 patients combined with systematic literature review and pooled analysis of PubMed, Web of Science, and Scopus search, identifying 576 papers. After excluding 307 papers as search engine duplicates, only 16 of the remaining papers had adequate patient data to be included. Our case series of 18 patients had a 2-year disease-free survival (DFS) and overall survival (OS) of 90.0% and 100%, respectively. The pooled analysis of 300 patients that had an endoscopic resection of recurrent NPC showed recurrence-free survival and overall survival were 85.8% and 82.9%, respectively. Most, 56.1%, were recurrent T1 lesions. Resection margins were negative in 90.2% of patients. Local recurrence occurred in 20.1% of patients. Major complications occurred in 13.6% of patients. The mean...

Head & Neck Surgery, 2016

The Laryngoscope, Jan 5, 2016

Low-grade myofibroblastic sarcoma (LGMS) is a rare entity that is described as having a predilect... more Low-grade myofibroblastic sarcoma (LGMS) is a rare entity that is described as having a predilection for occurring in the head and neck region. Here we analyze its demographics, clinic-pathologic, and survival characteristics. Retrospective database analysis. A cohort from the Surveillance, Epidemiology, and End Results Program database of cases with LGMS between 2001 and 2012. There were 49 cases with a 5-year overall survival of 71.6% and disease- specific survival of 76.3%. The majority of cases were in patients <60 years old, female, and white ethnicity. The most common sites were the extremities in 40.8% of cases followed by the head and neck region with 26.5% of cases. Multivariate analysis showed that only older age was significantly associated with worse survival (P < .05). LGMS is uncommon in the United States and occurs most commonly in the extremities followed by the head and neck region, despite an existing characterization of a predilection for the head and neck r...

European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery, Jan 20, 2016

Endoscopy is often used to screen for nasopharyngeal carcinoma. A normal nasopharynx on white lig... more Endoscopy is often used to screen for nasopharyngeal carcinoma. A normal nasopharynx on white light endoscopy may yet harbor subclinical or occult malignancy. This study assessed whether the vascular pattern seen on narrow band imaging endoscopy could indicate this and thus be useful for detecting suspected nasopharyngeal carcinoma. The nasopharynx of 156 patients who failed serological screening for or presented with symptoms of nasopharyngeal carcinoma was graded under white light and narrow band imaging endoscopy and a biopsy taken. The accuracy of assessing the nasopharynx as being probably or definitely malignant on white light endoscopy was high (area under the curve = 0.924), as it was of being normal on narrow band imaging endoscopy (=0.799). The sensitivity and specificity of white light and narrow band imaging endoscopy for nasopharyngeal carcinoma was 93 and 22 %, and 92 and 98 %, respectively. Significantly associated with nasopharyngeal carcinoma was a high index of sus...

Journal of cellular biochemistry, Nov 11, 2016

Oxidative stress-induced DNA damage is a known causing factor for many types of tumors, but infor... more Oxidative stress-induced DNA damage is a known causing factor for many types of tumors, but information on the role of oxidants and antioxidants in thyroid tumors is limited. The aim of this study was to determine antioxidant levels in thyroid tumors. In this study, tumor and its matched non-tumor thyroid tissue samples were obtained from 53 patients with thyroid tumors. The levels of manganese superoxide dismutase (MnSOD), thioredoxin reductase 2 (TXNRD2), glutathione (GSH), glutathione peroxidase (Gpx), catalase (CAT), and 27kd heat-shock protein (hsp27) were determined in both thyroid tissue samples and cultured thyroid cells by immunohistochemical staining and western blot. Hydrogen peroxide (H2 O2 ) was used to generate oxidant stress in the cell culture experiments. We found that the levels of MnSOD, TXNRD2, GSH, Gpx and Hsp27 were increased in both malignant and benign tumors, while the level of CAT was decreased. To verify the results of the tissue study, we treated cultured...

Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology, Jan 24, 2015

While the global incidence of human papillomavirus (HPV)-associated oropharyngeal squamous cell c... more While the global incidence of human papillomavirus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) is increasing, there is little information on southern Chinese population available. We analyzed 207 patients which constituted 63.5% of all newly diagnosed OPSCC in Hong Kong during a 5-year period from 2005 to 2009. We used E6/7 mRNA as a marker of oncogenic involvement and found 20.8% (43/207) of OPSCC and 29.0% (36/124) of tonsillar SCC were associated with HPV. HPV-16 was identified in all cases except one (HPV-18). Patients with HPV-associated OPSCC were significantly younger than HPV-negative patients (mean age: 59.8 vs 63.9 years, P=0.05). Multivariate analysis showed that HPV-associated OPSCC was more likely to occur in non-smokers (39.5 vs. 15.1%, OR: 2.89, P=0.05), non-drinkers (52.5 vs. 25.6%, OR: 2.72, P=0.04), originate from the palatine tonsils (83.7 vs. 53.7%, OR: 3.88, P=0.01), present with an early primary tumor (T1/2) (79.1 vs. 47.6%, OR: 3.81, P=0.004...

AJNR. American journal of neuroradiology, Jan 27, 2015

Our previous nasopharyngeal carcinoma detection study, comparing MR imaging, endoscopy, and endos... more Our previous nasopharyngeal carcinoma detection study, comparing MR imaging, endoscopy, and endoscopic biopsy, showed that MR imaging is a highly sensitive test that identifies nasopharyngeal carcinomas missed by endoscopy. However, at the close of that study, patients without biopsy-proved nasopharyngeal carcinoma nevertheless had shown suspicious abnormalities on endoscopy and/or MR imaging. The aim of this study was to determine whether there were any patients with undiagnosed nasopharyngeal carcinoma by obtaining long-term follow-up and to use these data to re-evaluate the diagnostic performance of MR imaging. In the previous study, 246 patients referred to a hospital ear, nose, and throat clinic with suspected nasopharyngeal carcinoma, based on a wide range of clinical indications, had undergone MR imaging, endoscopy, and endoscopic biopsy, and 77 had biopsy-proved nasopharyngeal carcinoma. One hundred twenty-six of 169 patients without biopsy-proved nasopharyngeal carcinoma un...

Journal of Medical Virology, 2015

HPV plays a role in the development of a portion of head and neck squamous cell carcinoma (HNSCC)... more HPV plays a role in the development of a portion of head and neck squamous cell carcinoma (HNSCC), but only limited information on its role in southern Chinese population is avavilable. A multicenter case-control study was conducted. HPV type, viral integration, E6/7 mRNA expression status, and TP53 mutation were determined. A total of 228 HNSCC were recruited inclduing 137 (60.1%) oral SCC, 34 (14.9%) oropharyngeal SCC, 31 (13.6%) laryngeal SCC, 21 (9.2%) hypopharyngeal SCC, and 5 (2.2%) lip and paranasal sinus SCC. High-risk HPV infection was found in 7.5% (17/228) of HNSCC, but only a small proportion of samples had evidence of viral integration (5.3%, 12/228) or E6/7 mRNA expression (4.4%, 10/228). HPV infection with oncogenic phenotype (integration and E6/7 mRNA expression) was significantly more common in oropharyngeal SCC than controls (9/34, 26.5% vs. 0/42, 0.0%, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Smoking showed a significant association with HNSCC, oropharyngeal SCC and laryngeal SCC. TP53 mutation was associated with HNSCC (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Older age, TP53 mutation, and HPV16 infection with oncogenic phenotypes were independently associated factors for HNSCC with odds ratios of 1.03 (1.02-1.05), 3.38 (1.71-6.66) and 9.19 (1.13-74.68), respectively. High-risk HPV infection of head and neck mucosa is not uncommon in the Hong Kong population. This study found that 26-30% of oropharyngeal carcinoma was associated with HPV infection, mostly HPV16, and that smoking which predisposes to TP53 mutations was another important risk factor. This article is protected by copyright. All rights reserved.

Head & Neck, 2015

Non-nasopharyngeal head and neck lymphoepithelioma-like carcinoma (LELC) is a rate entity. The pu... more Non-nasopharyngeal head and neck lymphoepithelioma-like carcinoma (LELC) is a rate entity. The purpose of this study was to analyze its demographic, clinicopathologic, and survival characteristics. A cohort from the Surveillance, Epidemiology, and End Results (SEER) database of cases with non-nasopharyngeal head and neck LELC between 1973 and 2011. There were 378 cases with 5-year overall survival (OS) of 70.5% and disease-specific survival (DSS) of 77.7%. The majority of cases were &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;60-year-old white men. Salivary gland LELC had the highest OS (80.8%) and DSS (85.7%) at 5 years. Multivariate analysis showed that older age, no surgery, and no radiation were independently significantly associated with worse survival (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .05). Non-nasopharyngeal head and neck LELC is uncommon in the United States with salivary gland LELC having the highest OS and DSS compared with other head and neck sites. The optimal treatment with surgery and/or radiotherapy needs to be further investigated. © 2015 Wiley Periodicals, Inc. Head Neck, 2015.

Oral Oncology Supplement, 2009

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde, 1986

An unusual case of airway obstruction is presented. The importance of communication between all p... more An unusual case of airway obstruction is presented. The importance of communication between all physicians caring for a patient is stressed. The need for correct and precise documentation of procedures performed is highlighted.

The Annals of otology, rhinology, and laryngology, 2010

We developed an objective endoscopic score of abnormality of the nasopharynx to predict the likel... more We developed an objective endoscopic score of abnormality of the nasopharynx to predict the likelihood of malignancy. A score sheet with 44 variables was developed to objectively quantify the bilateral endoscopic assessment of the nasopharynx. Patients scheduled to undergo nasopharyngeal biopsies were recruited. The nasopharynx was assessed endoscopically, photographed, and scored on 44 variables. The scores were compared to the biopsy results, and predictors of malignancy were modeled with regression analysis. The sensitivity and specificity of the novel scoring system were examined. Seventeen patients had carcinoma, and 60 had a benign lesion or no disease. Patients with a nasopharyngeal malignancy scored significantly higher than did patients with a benign lesion or no disease. No patient with a malignant lesion had a score of less than 12. With a receiver operating characteristic curve area of 0.917, the score demonstrated an excellent ability to discriminate between nasopharyng...

Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2008

To investigate whether the approach used to the nasopharynx to perform a salvage nasopharyngectom... more To investigate whether the approach used to the nasopharynx to perform a salvage nasopharyngectomy for recurrent or residual nasopharyngeal carcinoma influences survival. A retrospective case series. Eighty patients underwent a nasopharyngectomy via a transpalatal, maxillary swing, or midfacial degloving approach. Local progression-free, locoregional progression-free, and overall survival rates were calculated for each approach. For the whole group (N = 80), there were no significant differences in the survival rates between the three approaches. For the subgroup of patients with recurrent T1 and T2 tumors (n = 68), the local progression-free and locoregional progression-free survival rates were significantly better when a maxillary swing approach was used than when a midfacial degloving approach was used. The maxillary swing approach is associated with significantly better survival rates than the midfacial degloving approach when used to perform a salvage nasopharyngectomy for resi...