Prospective evaluation of weekly concomitant tumor bed boost with three-week hypofractionated whole breast irradiation in early breast cancer

Objectives A prospective study was conducted to assess the acute and late toxicity of hypofractionated whole breast irradiation with a weekly concomitant boost for women with early breast cancer (EBC). Methods Women with EBC who underwent breast-conserving surgery were eligible. A dose of 40Gy in 15 fractions over 3 weeks was delivered to the whole breast with a concomitant weekly boost to the post-operative cavity of 3Gy in three fractions. Toxicity was graded using the Radiation Therapy Oncology Group (RTOG) acute toxicity and RTOG/EORTC late toxicity scales. Results A total of 67 women were enrolled with a median age of 49 years (range 31–69). Median follow-up was 25 months (range 11–34). Acute skin reactions included grade (G) 1 ( n = 47, 70%), G2 ( n = 10, 13%), and G3 ( n = 1, 1.5%). Late skin toxicity was observed in 13 patients (19%), all of whom experienced G1 toxicity only. On multivariable analysis, diabetes mellitus was predictive of acute skin toxicity ( p = 0.003), while age less than 50 years ( p = 0.029) and diabetes mellitus ( p = 0.013) were predictive of late skin toxicity. Conclusions Whole breast irradiation with concomitant weekly boost appears feasible and safe. Further investigation is required to fully evaluate this schedule as an alternative to conventional whole breast irradiation with a sequential boost.