Introduction: Various dose fractionation schemes including conventional fractionation and hypofractionation, are in use for chest wall irradiation in carcinoma breast. Hypofractionation includes a higher dose per fraction with a smaller number of fractions with a biologically equivalent dose.

Aims: To study, analyse and compare the dosimetric and clinical outcomes using conventional fractionation versus hypofractionation. Methods and materials: This observational study includes 20 post-mastectomy patients and is randomized into two arms, with 10 patients in each arm. One arm received radiation as per conventional fractionation, and the other arm received it as per hypofractionation. 3 DCRT plans were generated, and doses to organs at risk were analysed and compared between the two groups. Patients were assessed for acute and late toxicities on follow-up, anda comparison was done between both groups.

Results: Mean dose (D mean) in ipsilateral spine, lung, esophagus, trachea, and, thyroid showed statistically significant difference. The V25 and D mean in the heart, Liver showed no statistically significant difference. Acute toxicities were higher in conventional groups, with higher grades, while late toxicities were equivalent.

Conclusion: Hypofractionation significantly reduces mean doses to organs at risk and toxicities, with comparable locoregional control; hence it is comparable to and can be used in place of conventional fractionation in post-mastectomy breast cancer patients for chest wall irradiation.