Dose-volume Analysis of Heart and Lung during ۳D planning of Tangential Breast Cancer Irradiation

Background: Breast cancer is becoming more frequently diagnosed at early stages with improved long term outcomes. Radiation-related heart disease and lung cancer can occur following radiotherapy for breast cancer. The aim of this study was to evaluate some dosimetric parameters of heart and lung during whole breast radiotherapy. Methods:Twenty five consecutive patients with breast cancer who underwent radiotherapy were included in this study. Plans that employed the ۳D conventional radiotherapy technique (Tangential Technique) were generated for each patient. Dose-volume histograms (DVHs) were calculated and dosimetric parameters such as, mean dose/volume receiving a dose ۳۰ Gy (V۳۰), mean dose/ volume receiving a dose ۲۰ Gy (V۲۰) for heart and lung were assessed, respectively. Results:The average of mean dose of heart on left and right side irradiation was ۹.۶۸±۵.۱۰ Gy and ۱.۲۳±۱.۵۱ Gy, respectively. The average of mean dose of ipsilateral lung on left and right side irradiation was ۱۴.۴۹±۴.۰۷ Gy and ۱۱.۶۹±۳.۳۷ Gy, respectively. The percentage of heart volume that received at least ۳۰ Gy was ۱۶.۳۲±۹.۵۶% for the left-sided treatment. The percentage of lung volume that received at least ۲۰ Gy was ۲۳.۴۷±۱۱.۰۵% and ۲۴.۱۲±۷.۷۷% respectively on the left and right-sided breast irradiation. Conclusion: Tangential beam conventional radiotherapy of the chest wall of postmastectomy breast cancer patients provides the potential to significantly keep the DVH parameters of heart and lung as low as the QUANTEC constrains.

Keywords:

radiotherapy , Tangential Breast Technique , Dose-volume Histograms , Heart , Lung