PD-0467: Adaptive, preoperative radiotherapy with image guided Tomotherapy concomitant with chemotherapy in rectal cancer (original) (raw)
Related papers
In Vivo
Background/Aim: T2 weighted magnetic resonance (MR) imaging is the gold standard for locally advanced rectal cancer (LARC) staging. The potential benefit of functional imaging, as diffusion-weighted MR (DWI) and positron emission tomography-computed tomography (PET-CT), could be considered for treatment intensification strategies. Dose intensification resulted in better pathological complete response (pCR) rates. This study evaluated the inter-observer agreement between two radiation oncologists, and the difference in gross tumor volume (GTV) delineation in simulation-CT, T2-MR, DWI-MR, and PET-CT in patients with LARC. Patients and Methods: Two radiation oncologists prospectively delineated GTVs of 24 patients on simul-CT (CT GTV), T2-weighted MR (T2 GTV), echo planar b1000 DWI (DWI GTV) and PET-CT (PET GTV). Observers' agreement was assessed using Dice index. Kruskal-Wallis test assessed differences between methods. Results: Mean CT GTV , T2 GTV , DWI GTV , and PET GTV were 41.3±26.9 cc, 25.9±15.2 cc, 21±14.8 cc, and 37.7±27.7 cc for the first observer, and 42.2±27.9 cc, 27.6±16.9 cc, 19.9±14.9cc, and 34.8±24.3 cc for the second observer, respectively. Mean Dice index was 0.85 for CT GTV , 0.84 for T2 GTV , 0.82 for DWI GTV , and 0.89 for PET GTV , representative of almost perfect agreement. Kruskal-Wallis test showed a statistically significant difference between methods (p=0.009). Dunn test showed there were differences between DWI GTV vs. PET GTV (p=0.040) and DWI GTV vs. CT GTV (p=0.008). Conclusion: DWI resulted in smaller volume delineation compared to CT, T2-MR, and PET-CT functional images. Almost perfect agreements were reported for each imaging modality between two observers. DWI-MR seems to remain the optimal strategy for boost volume delineation for dose escalation in patients with LARC. Standard treatment for locally advanced rectal cancer (LARC) is represented by neoadjuvant chemoradiotherapy (CRT) followed by organ preservation surgery. It is well known that clinical outcomes depend on the results of these treatments, in particular related to pathological complete response (pCR). Response to neoadjuvant CRT is dose-dependent with pCR rates reaching 20.4% using treatment intensification, when dose escalation above 60 Gy are delivered (1). Furthermore, both better dose distribution to the target as well as sparing the adjacent small bowel and other organs at risk (OARs) can be obtained with modern radiotherapy 424
Academic Radiology, 2019
Rationale and Objectives: This study aimed to investigate the predictive value of pre-/postneoadjuvant chemoradiotherapy (nCRT) magnetic resonance imaging (MRI) characteristics for the long-term survival outcomes in patients with locally advanced rectal cancer (LARC). Materials and Methods: We retrospectively evaluated pre-and post-nCRT MRI and clinicopathologic characteristics of LARC patients. The 3-year disease-free survival (DFS) was estimated using the Kaplan-Meier product-limit method. Associations between MRI variabilities and survival outcomes were assessed using Cox proportional hazards model. Results: In total, 171 LARC patients (112 men and 59 women) with a median age of 55 years (range, 27À82 years) treated with nCRT were evaluated. The median follow-up was 47.6 months, and the 3-, 4-, and 5-year DFS in the overall cohort was 76.6%, 74.5%, and 73.7%, respectively. MRI assessment of extramural venous invasion (mrEMVI) positivity was a significant independent adverse factor of longterm survival (hazard ratio [HR] = 2.589, 95% confidence interval [CI] = 1.398À4.794, p = 0.002) on multivariate analysis. Patients with positive mrEMVI had significantly lower 3-year DFS than those with negative mrEMVI (52.6 months vs 65.1 months; p = 0.003). Moreover, the tumor regression grade on MRI (mrTRG) also significantly correlated with survival outcomes in patients with LARC. Patients with partial response on post-nCRT MRI (mrPR) showed short DFS than those with complete response (mrCR; HR = 4.914, 95% CI = 1.176À20.533, p = 0.029). The 3-year DFS of mrCR and mrPR patients were 74.3 months and 58.9 months, respectively (p = 0.011). Conclusion: The pre-/post-nCRT MRI characteristics may be used to long-term survival stratification in LARC patients. mrEMVI positivity was an independent adverse prognostic indicator for 3-year DFS. Further, mrTRG may also be a predictive factor for the prognosis of LARC patients. The pre-/post-nCRT MR imaging may offer more information for providing individualized treatment.
MRI for evaluation of treatment response in rectal cancer
The British Journal of Radiology, 2016
MRI plays an increasingly pivotal role in the clinical staging of rectal cancer in the baseline and post-treatment settings. An accurate evaluation of response to neoadjuvant treatment is crucial because of its major influence on patient management and quality of life. However, evaluation of treatment response is challenging for both imaging and clinical assessments owing to treatment-related inflammation and fibrosis. At one end of the spectrum are clinical yT4 rectal cancers, wherein precise post-treatment MRI evaluation of tumour spread is particularly important for avoiding unnecessary exenterative surgery. At the other extreme, for tumours with clinical near-complete response or clinical complete response to neoadjuvant treatment, less invasive treatment may be suitable instead of the standard surgical approach such as, for example, a "Watch and Wait" approach or perhaps local excision. Ideally, the goal of post-treatment MRI evaluation would be to identify these subgroups of patients so that they might be spared unnecessary surgical intervention. It is known that post-chemoradiation therapy restaging using conventional MR sequences is less accurate than baseline staging, particularly in confirming T0 disease, largely owing to the difficulty in distinguishing fibrosis, oedema and normal mucosa from small foci of residual tumour. However, there is a growing utilization of multiparametric MRI, which has superseded other types of evaluations and requires review and periodic re-evaluation. This commentary discusses the current status of multiparametric MRI in the post-treatment setting and the challenges facing imaging in general in the accurate determination of treatment response.
Revista Española de Medicina Nuclear e Imagen Molecular (English Edition), 2020
Objective: Our aim is to evaluate if different metabolic parameters obtained by 18 F-FDG PET/CT and diffusion weighted magnetic resonance imaging (DW-MRI) can aid in neoadjuvant radiochemotherapy (RCT) response assessment in locally advanced rectal cancer (LARC) patients. Methods: Out of 20 LARC patients, who were planned to receive neoadjuvant RCT, 19 were included in this prospective study. Patients had 18 F-FDG PET/CT and DW-MRI at initial staging, interim (2 weeks after onset of RCT) and after completion of RCT (post-therapy). Standardized uptake value (SUV) parameters (SUVmax, SUVmean, SUVpeak, SULpeak), metabolic tumor volume (MTV) and tumor lesion glycolysis (TLG) detected on PET images and apparent diffusion coefficient (ADC) values (for b = 400 and b = 1000 s/mm 2) obtained from DW-MRI were recorded. Postoperative tumor regression grade (TRG) was used as gold-standard, except for 2 patients who were under complete remission with non-operative management 19 months post-therapy and scored as responders. Results: On interim PET/CT, no significant difference was found among PET parameters between responders and non-responders, whereas post-therapy SUVmax, SUVpeak, MTV, SULpeak, TLG (p = 0.02, p = 0.014, p = 0.025, p = 0.007, p = 0.02, respectively) and initial MTV (p = 0.034) were significantly lower in responders. ADC response index (RI) was higher in responders (interim p = 0.026; post-therapy: p = 0.018) and ROC analysis revealed that a threshold of ADC RI > 41.6% for interim MRI and >44.6% for post-therapy MRI had sensitivity and specificity of 75.0% and 90.9%, respectively. Conclusions: While interim 18 F-FDG PET/CT failed to predict therapy response during RCT, post-therapy PET could accurately differentiate responders. DW-MRI was found to be more promising in interim detection of RCT response.
Annals of Surgical Oncology, 2013
Background. Most current guidelines recommend neoadjuvant short course radiotherapy (sRT) or radiochemotherapy (nRCT) for rectal cancer stage II and III. After the introduction of total mesorectal excision (TME) and magnetic resonance imaging (MRI), this proceeding has been questioned and omission of neoadjuvant treatment according to preoperative MRI-criteria has been propagated. Aim of the present paper is to review the state of evidence regarding MRI-based treatment decision depending on the predicted width of the circumferential resection margin (CRM). Methods. A comprehensive survey of the literature was performed using the search terms ''rectal cancer'', ''radiotherapy'', ''radio-chemotherapy'', ''MRI-based therapy'', ''circumferential resection margin''. Data from lately published observational studies were compared to results from randomized trials and outcome analyses of the Norwegian national cancer registry. Results. Only one observational study using MRI-based treatment according to the anticipated CRM provided 5 year local recurrence data, however only for 65 patients. The second study did not yet evaluate recurrence rates. Two randomized trials comparing sRT to primary TME showed significantly worse outcome for non-irradiated patients. Data from the Norwegian rectal cancer registry demonstrate that TME alone is associated with higher LRR than achievable with preoperative RT. Conclusions. Current evidence does not support the omission of neoadjuvant treatment for stage II-III rectal cancer on the basis of an MRI-predicted negative CRM. Randomized studies are warranted to clarify whether and for which subgroups TME alone is safe in terms of local recurrences.
Imaging for Target Volume Delineation in Rectal Cancer Radiotherapy — A Systematic Review
Clinical Oncology
The global move towards more conformal radiotherapy for rectal cancer requires better imaging modalities that both visualise the disease accurately and are reproducible; to reduce interobserver variation. This review explores the advances in imaging modalities used in target volume delineation, with a view to make recommendations for current clinical practice and to propose future directions for research. A systematic review was conducted using MEDLINE and EMBASE. Articles considered relevant by the authors were included. Planning with orthogonal films is being replaced by computed tomography (CT) simulation. This is now considered the 'gold standard' and allows conformal three-dimensional planning. Magnetic resonance imaging (MRI) has been shown to overcome some of the limitations of CT and can be used either as a diagnostic image to visually aid planning, or as a 'planning' MRI carried out in the treatment position and co-registered with the planning CT. The latter approach has been shown to change the treated volumes compared with CT and in prostate cancer patients has been shown to reduce interobserver variation. There are remaining issues with four-dimensional motion that are yet to be fully appreciated or overcome. 2-[18F] fluoro-2-deoxy-D-glucose positron emission tomography/CT co-registered with planning CT results in smaller volumes than CT alone and also reduces interobserver variation, but requires further validation before routine implementation. Experimental work utilising novel positron emission tomography tracers and diffusionweighted MRI shows promise and requires further evaluation. Rigorous quality assurance is important with processing of newer imaging modalities. Further work needs to be conducted into both interobserver variation and the formal evaluation of the clinical benefits of newer imaging modalities. Developments in imageguided radiotherapy are also required to ensure that improvements in target definition at the planning stage are reproducible throughout treatment.
Abdominal Radiology
Purpose Pre-treatment knowledge of the anticipated response of rectal tumors to neoadjuvant chemoradiotherapy (CRT) could help to further optimize the treatment. Van Griethuysen et al. proposed a visual 5-point confidence score to predict the likelihood of response on baseline MRI. Aim was to evaluate this score in a multicenter and multireader study setting and compare it to two simplified (4-point and 2-point) adaptations in terms of diagnostic performance, interobserver agreement (IOA), and reader preference. Methods Twenty-two radiologists from 14 countries (5 MRI-experts,17 general/abdominal radiologists) retrospectively reviewed 90 baseline MRIs to estimate if patients would likely achieve a (near-)complete response (nCR); first using the 5-point score by van Griethuysen (1=highly unlikely to 5=highly likely to achieve nCR), second using a 4-point adaptation (with 1-point each for high-risk T-stage, obvious mesorectal fascia invasion, nodal involvement, and extramural vascular...
Current Topics in Colorectal Surgery [Working Title], 2021
Rectal cancer is one of the most common types of cancer in both men and women. In recent years, the importance of magnetic resonance imaging (MRI) has greatly increased in the multidisciplinary treatment of patients with rectal cancer. MRI has a particularly important role in the most accurate preoperative staging of these patients, both in terms of assessing the local invasion of the tumor and in terms of assessing the status of pelvic lymph nodes. Many patients with rectal cancer, especially those in the advanced stage of the disease, in the preoperative period undergo neoadjuvant radio chemotherapy. The evaluation of the clinical response of these patients to neoadjuvant therapy is of crucial importance both in terms of personalized treatment and in terms of their prognosis. In this regard, MRI has its clearly defined role at present in evaluating the efficacy of neoadjuvant therapy, as well as in postoperative follow-up.
Journal of Radiotherapy in Practice, 2021
Aim:The aim of this systematic review was to synthesise and summarise evidence surrounding the clinical use of fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) and magnetic resonance imaging (MRI) for target volume delineation (TVD) in rectal cancer radiotherapy planning.Methods:PubMed, EMBASE, Cochrane library, CINAHL, Web of Science and Scopus databases and other sources were systematically queried using keywords and relevant synonyms. Eligible full-text studies were assessed for methodological quality using the QUADAS-2 tool.Results:Eight of the 1448 studies identified met the inclusion criteria. Findings showed that MRI significantly delineate larger tumour volumes (TVs) than FDG-PET/CT while diffusion-weighted magnetic resonance imaging (DW-MRI) defined smaller gross tumour volumes (GTVs) compared to T2 weighted-Magnetic Resonance Image. CT-based GTVs were found to be larger compared to FDG-PET/CT. FDG-PET/CT also identified new lesions in ...