Whole-breast hypofractionated IMRT and brachytherapy boost after conservative surgery for breast cancer: Early results of a prospective non-randomised trial.

46 Background: To report early results obtained in a prospective group of patients (pts) treated with whole breast IMRT radiotherapy plus a brachytherapy boost to the tumor bed after conservative surgery, given either with hypofractionated or normofractionated radiotherapy. Methods: Between 12/2008 and 06/2014, 829 pts with <4cm, N0-2 breast cancers treated with conservative surgery were assigned to enter the study. Pts were offered to be treated either with IMRT hypofrationated whole breast and lymphnode areas (if needed) radiotherapy 42.6 Gy (266cGyx16 fractions) plus a 7 Gy boost to the tumor bed, (hypofractionated group) or IMRT normofractionated 50 Gy (200cGyx25) to the whole breast and lymphatic areas (when needed) plus 16 Gy brachytherapy boost (200cGyx8 fractions) (normofractionated group). Treatment assignation was done according to the patients preference or, if none, were randomly assigned to have both groups uniformly balanced. During treatment and follow-up special attention was taken to early and late side-effects, breast fibrosis, arm lymphedema, skin reaction, patient satisfaction and local, regional and distant disease control. Results: A total of 309 pts were included in the hypofractionated group and 520 in the normofractionated group. All patients completed treatment. Pts were evaluated weekly during treatment and every 3 months for the first 2 years of follow-up and in a yearly basis after. Photographs were taken at each visit. SOMA-LENT scales were used in every visit. For quality of life EORTC QLQ-C30 plus the BR-15 module were used. No pts had adverse side-effect that required treatment ending in any group. In the hypofractionated group, there were 1 LR, 1 M1 and 1 death due to the disease. In the normofractionated group there were 12 LR, 7 M1 and 4 patients died due to the disease. Conclusions: Hypofractionated IMRT to the whole breast followed by a 1 fraction HDR breast implant was a safe and effective method of treatment for early breast cancer treated with conservative surgery, even in those patients N+ in which the supraclavicular fossa was included in the treatment fields. Pts satisfaction was greater in the hypofractionated group.