Hypofractionated radiotherapy in post mastectomy locally advanced breast cancer: a study from a regional cancer center in North East India

Background: Adjuvant radiotherapy has increased local-regional and overall survival rates in breast cancer. Conventional fractionation delivering 50-60 Gray (Gy) over 5-6weeks is a standard approach. A shorter duration of hypofractionated treatment will be more convenient for patients and treatment providers if found safe and equally effective.Methods: Around 50 high risk breast cancer patients who underwent mastectomy were enrolled and randomized into the study arms- CF (Conventional Fractionation) Arm (50Gy/25 Fr @ 2 Gy/fraction/day 5 days a week over 5weeks) and HF (Hypo-Fractionation) arm (40.05 Gy/15 Fr @ 2.67 Gy/fraction/day 5 days a week over 3weeks). Treatment related acute and late toxicities, loco-regional recurrence; distant metastasis and survival rates were recorded for comparison.Results: Twenty-five patients were enrolled in each arm with baseline characters well matched. At median follow up of 44 months, OS was 80% in HF arm against 64% in CF arm (p-value: 0.292). HF arm also showed better DFS at 4 years of 76% compared to 64% in CF arm (p-value: 0.411). Although the difference was not significant statistically, the Hazard Ratio of 1.543 (95% CI: 0.549-4.339) for DFS and 1.801 (95% CI: 0.603-5.377) for OS indicated trends towards better outcomes in HF arm in terms of disease control and survival. Acute and late toxicities were also lesser in HF arm, though not statistically significant (all p-values >0.05).Conclusions: In post mastectomy setting, HFRT is comparable to CFRT in terms of safety and efficacy, will be more convenient for patients and care givers and hence can be a routine standard practice

Determination of optimal clinical target volume to planning target volume margins for conformal radiotherapy planning using image guidance system in rectal cancer in prone position

Context: In advanced radiotherapy techniques such as three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT), geometrical uncertainties are very crucial as they may lead to under dosing of tumor and over dosing of the nearby critical structures and hence, it is important to determine planning target volume (PTV) margins which are specific for every center. Aims: The aim of this study is to determine adequate clinical target volume (CTV) to PTV margins specific to our radiotherapy center. Settings and Design: To calculate CTV to PTV margins for rectal cancer patients in prone position using kV cone beam CBCT data sets. Materials and Methods: With the Patient immobilized in prone position using thermoplastic mask, a CT simulation was done and a comprehensive 3DCRT plan was generated. Daily kV CBCT was done to check the patient setup error. Daily setup errors were recorded and evaluated retrospectively. Results: CTV-PTV margin calculated for pelvis in the prone position was calculated using van Herk Formula and were found to be 0.5, 1.8, 0.7 cm in the lateral, longitudinal, and vertical directions, respectively. Conclusions: Image guidance is an effective method to evaluate patient setup errors. Good quality immobilization devices and stringent patient setup policies can help to reduce PTV margins further