Skin and lung toxicity in synchronous bilateral breast cancer treated with volumetric-modulated arc radiotherapy: a mono-institutional experience.

Abstract

To evaluate acute and late skin/subcutaneous toxicities and radiation-induced lung fibrosis (RILF) in patients treated with adjuvant radiotherapy (RT) for synchronous bilateral breast cancers (SBBC), after conservative surgery. Twenty-five patients were treated with volumetric-modulated arc therapy (VMAT/RapidArc®) on both breasts, and checked clinically for detecting RT toxicities during and after treatment. A high-resolution computed tomography (HRCT) was performed, for detecting RILF during follow-up. We registered acute Grade-1 skin toxicity in 18 patients (72%), while six patients (24%) experienced Grade-2 toxicity. No breath symptoms were reported during and after RT. Late Grade-1 subcutaneous toxicity and late Grade-2 skin toxicity were registered in four patients (16%) and one patient (4%), respectively, at a mean follow-up of 36months. Grade-1 RILF was detected in six patients (30%). The median volume of fibrosis area was 6.5cc (range 1.3-21.5cc). The partial volumes receiving a specified dose (V20, V30, V40, and V50) in patients who developed lung fibrosis were significantly bigger than who did not (p < 0.01). We showed that the mean volume of the tumour boost of patients who developed fibrosis (77.7cc) was not significantly different from the other patients (90.8cc) (p = 0.5). The clinical impact of this technique is favourable, and this is the first clinical study showing RILF by HRCT in a setting of SBBC. Further study with larger accrual is mandatory.