Background: Radiotherapy for left breast cancer may increase risk of cardiovascular diseases. Radiotherapy guidelines suggest dose-volume constrains for the whole heart but newer trends suggest that excessive dose to the Left Anterior Descending artery (LAD) endothelium may cause cardiac toxicity and henceforth dose constraints to LAD should be evaluated.

Purpose: The present study is to assess the dosimetric parameters of heart and LAD in left breast cancer patients treated with Intensity Modulated Radiotherapy.

Methodology: Twenty eight patients of left-sided breast cancer were treated from Jan to Dec 2022. Radiotherapy was given to chest wall and regional lymph node areas. Dose given to planning target volume was 50 Gy in 25 daily fractions over 5 weeks. Delineation of target volumes was done according to RTOG protocol. All patients were planned by IMRT technique. Dosimetric parameters of PTV (D95, D90, Dmean, Conformity Index and Homogeneity Index) along with V25 and mean doses of heart and LAD were evaluated. DVHs were calculated and compared.

Results: The mean value of PTV parameters was D95 – 46.71Gy, D90 – 48.13Gy, D mean – 49.83, Conformity Index – 0.85 and Homogeneity Index – 0.14. Dosimetric parameters of LAD was significantly higher than heart. D mean (39.5 Gy v/s 15.03 Gy; p-value < .00001), V25% (43 Gy v/s 23.4 Gy; p-value < .00001).

Conclusion: Dosimetric parameters of LAD along with heart should be evaluated to prevent late cardiac toxicities.

Dr. Diksha Chaturvedi has completed her M.D. in Radiation Oncology from Shri Ram Murti Smarak Institute of Medical Sciences, Bareilly (U.P) in 2022 and currently working as senior resident in the same institute.