Prospective evaluation of concomitant tumour bed boost with whole breast irradiation in patients with locally advanced breast cancer undergoing breast-conserving therapy

Abstract

Background and purpose To evaluate prospectively the feasibility of concomitant weekly tumour bed electron boost along with whole breast radiotherapy (RT) following breast-conserving therapy (BCT) in patients with locally advanced breast cancer (LABC) with the aim of reducing overall treatment time. Materials and methods Thirty patients with LABC suitable for BCT following neoadjuvant chemotherapy (CAF/CEF) were accrued in the study. Conventional RT (CRT) to the whole breast was delivered 5 days a week to a dose of 50 Gy using 6–10 MV photons. In addition, an electron boost to the tumour bed was delivered every Saturday, eventually delivering 5 such weekly fractions to a boost dose of 12.5 Gy. Patients were evaluated for acute reactions during the treatment and cosmetic evaluation was done before, at the end of radiation therapy and at follow up by 2 independent observers blinded to each other. The study population (concomitant boost (CB) group) was compared with a similar cohort of 32 patients treated conventionally with tumour bed boost of 15 Gy in 6 fractions delivered after the completion of whole breast irradiation (CRT group). Results All patients completed RT within the stipulated time with no grade IV skin toxicity in either group. At conclusion of RT, in the CB group, confluent moist desquamation (grade III) developed within the tumour bed region in 1 patient (3.3%) and outside tumour bed region in 3 patients (10%). In the CRT group, 3 and 4 patients (9.4% and 12%) developed moist desquamation within and outside the tumour bed regions, respectively. CB did not affect the global cosmesis as compared with CRT group ( p=0.23) at the end of 3 years. Conclusion Concomitant tumour bed boost along with whole breast RT appears to be safe and feasible in a select group of patients. As the treatment is completed earlier by 6–10 days than conventional practice, it has favourable time and resource implications, particularly attractive for patients travelling long distances for treatment. Based on these encouraging results, we are planning to confirm the results in an appropriately designed and powered randomised trial.