Choondal Devan Sivanandan’s research while affiliated with Regional Cancer Centre and other places

Background Radical chemoradiation is the standard of treatment for locally advanced squamous cell carcinoma of esophagus and for patients with operable disease, but who are medically unfit or unwilling for surgery. As the esophagus is a central organ, the planning target volume (PTV) is central, lies close to the spinal cord and heart, and is surrounded by the lung, which is a radiosensitive organ. Irradiation of these critical structures is reduced by the use of three-dimensional conformal radiation therapy (3DCRT). Intensity-modulated radiation therapy (IMRT) has the potential to improve the uniformity of dose distribution to the tumor and reduce the dose received by surrounding normal tissues. Aim and Objectives 1. To compare the dose distribution, conformity, and homogeneity indices in radical radiotherapy of squamous cell carcinoma of esophagus using 3DCRT and IMRT techniques 2. To compare the doses received by critical structures such as heart, lung, spinal cord, and liver Materials and Methods All cases of squamous cell carcinoma esophagus treated with radical chemoradiation to a dose of 50 Gy in 25 fractions using 3DCRT technique from January 2018 to July 2019 were included. IMRT plans were generated for these cases. The parameters that represent dose distribution to the target volume and the dose received by the organs at risk were obtained from the dose–volume histogram. The difference in the mean values of the parameters between the two techniques was calculated. The statistical significance of the difference was determined using Student’s t-test and Wilcoxon signed-rank test. Results The volume of PTV receiving 105% and 107% of prescribed dose was significantly lower with IMRT (3.540% and 0.008%, respectively) compared to 3DCRT (7.654% and 0.623%). The homogeneity index was better with IMRT (0.088 vs. 0.107) than 3DCRT. Conformity index was found to be better with IMRT (1.149 vs. 1.573). Mean heart dose (18.216 vs. 24.591 Gy) and the volume of heart receiving 30 Gy were reduced with IMRT. The volume of lung receiving 20 Gy and the volume receiving 5 Gy were not significantly different between 3DCRT and IMRT. Maximum dose to spinal cord was similar with 3DCRT and IMRT. Conclusions IMRT avoids areas of excessive irradiation within the PTV. IMRT improves dose conformity to the target volume and homogeneity of dose distribution within the PTV. The cardiac dose is significantly reduced with IMRT. The mean lung dose remains similar to 3DCRT. There is no significant increase in the volume of lung receiving low-dose radiation with IMRT.

Purpose: This retrospective analysis is aimed to report the single institution experience from an Asian country utilizing Intensity Modulated Radiotherapy (IMRT) based Chemo radiation in Anal Canal Squamous Cell Carcinoma (ASCC) with an emphasis on efcacy, toxicity and disease and treatment-related variables associated with outcomes. Study was conduc Materials And Methods: ted in the department of Radiation Oncology at Regional Cancer Center, Thiruvananthapuram. All Patients with biopsy proven ASCC diagnosed between January 2014 and December 2018 and receiving curative intent IMRT were identied and follow up data till December 2020 was collected. Primary end point was Disease-free survival (DFS). Secondary end points were Overall Survival (OS), Colostomy-free survival (CFS) Loco regional Failure (LRF) and Toxicities. A total of 34 patients were analyzed during a median follow up of Results: 34 months. Twenty ve patients (73.5%) were in stage IIIB. Median overall treatment time was 36 days. The estimated two year DFS, OS and CFS were 79.4 %, 93.9 %and 97% respectively. Disease recurrence at any point on follow up occurred in ve patients (14.7%). Primary Tumor size of more than or equal to 5 cm and development of grade three anemia during RT was associated with inferior DFS in Univariate analysis. Patients taken less than two cycles of chemotherapy, there was a trend for inferior OS. Acute grade 3 or more dermatological toxicities was 44% and hematological toxicity was 35.3%. Radiotherapy break occurred in 38.2%of patients with a median of 5.5 days (range 2-13). Of the available patients chronic toxicities were reported for 40% and were of grade 2. IMRT is associated with favorable toxicity rates and excellent Conclusion: long-term efcacy in Asian population also where patients are presenting in an advanced stage. Reducing the total treatment time by SIB technique may improve the clinical outcome.

Background To compare the dosimetric outcomes of volumetric arc radiotherapy (RapidArc), intensity-modulated radiotherapy (IMRT), and 3D conformal radiotherapy (3DCRT) plans for primary liver tumours. Methods 7 patients with localised unresectable hepatocellular carcinoma were included in this study. CT simulation was done with voluntary deep inspiratory breath-holding after administering 80–90 mL of intravenous iodinated contrast. The mean tumour size was 5.6 cm (range 2.1–9.8) and two patients had multiple lesions (range 1–3). All patients were planned for partial liver irradiation for a total dose of 50–66 Gy in 2 Gy per fraction with conformal techniques. 3DCRT, IMRT, and RapidArc plans were generated using Eclipse planning system v.13 and dosimetric analysis was done to evaluate the plan quality and efficiency, including CI, HI, MU delivered, PTV Dmean and Dmax. IMRT plans had 3–5 fields and RapidArc plans had 3–5 arcs. V10,V20,V30 and V40 of normal liver and Dmean of organs at risk (OAR) and Dmax of spinal cord were also evaluated. Analysis was done using ANOVA and paired t-test with two tailed p < 0.05. Findings All the three techniques had comparable PTV coverage, dose homogeneity, and OAR sparing. IMRT and Rapid Arc had a significantly better conformity index than 3DCRT (p = 0.03). The high dose areas within the normal liver; V40 and V30 were significantly lower in RapidArc and IMRT plans (p = 0.03 and p = 0.04, respectively), although no significant differences were noted between IMRT and RapidArc. One patient could not attain the normal liver constraint V33 <33 Gy, which was attained with both IMRT and RapidArc plans. Interpretation RapidArc and IMRT provide better normal liver sparing and conformity than 3DCRT. However, RapidArc was not better than IMRT for liver protection. Further large trials are required to clearly establish the benefits of IMRT and Rapid Arc techniques to treat primary liver tumours.