Synchronous bilateral breast cancer patients treated with hypofractionated bilateral breast irradiation: A dosimetric and clinical study.

Abstract

Bilateral breast irradiation is technically challenging and there is limited information regarding optimal technique and outcomes. Hypofractionated Radiotherapy (HFRT) has emerged as the new standard of care in early breast cancer. However, there are concerns in using hypofractionation for bilateral breast irradiation due to larger volumes and potential toxicity. Our aim was to analyze the dosimetric data and clinical outcomes in these patients. Patients with synchronous bilateral breast cancer (SBBC) treated with bilateral breast irradiation were analyzed. All patients received simultaneous bilateral breast with or without regional nodal irradiation using a hypofractionated schedule of 40 Gy in 15 fractions over 3 weeks with single isocenter bi-tangential field-in-field intensity-modulated radiation therapy (FIF-IMRT) technique. Seven patients of SBBC were treated at our institute from 2015 to 2017. All patients were postmenopausal females. Five patients underwent bilateral modified radical mastectomy; two patients underwent bilateral breast conservative surgery. All patients received systemic anthracycline-based chemotherapy. The mean cardiac dose was 3.73 ± Gy and V 25 was 3.26% ± 1.96%. V 20 of lung ranged from 23.48% ± 4.47% and the mean esophageal dose was 3.6 ± 2.00 Gy. No patient had acute toxicity higher than Grade 2. At a median follow-up of 48 months, one patient died due to systemic progression. No patient reported any late toxicity. Bilateral breast irradiation using a hypofractionated schedule with single isocenter FIF-IMRT technique is technically feasible with minimal acute toxicity and no significant late effects on early follow-up.