A randomised controlled trial to evaluate both the role and optimal fractionation of radiotherapy in the conservative management of early breast cancer.

Abstract

Abstract Abstract #5125 Background: Postoperative radiotherapy is routinely used in early breast cancer using 50Gy in 25 daily fractions (Long). Both the role of radiotherapy and shorter regimens require validation.
 Methods: Patients with clinical stage 1 and 2 disease were randomised to receive immediate postoperative (RT) or delayed salvage treatment (No RT). Patients receiving RT were further randomised to Long or Short (40Gy in 15 daily fractions) regimens. The primary outcome measure was time to first relapse. Reported results are at median follow up of 16.9 years (IQR 15.4 - 18.8).
 Results: 707 women were recruited between 1985 and 1992: median age 59 years (range 28-80), 72% post menopausal, median tumour size 2.0cms (range 0.12-8.0). 271 patients have relapsed: 110 RT, 161 No RT. Site of first relapse was reported as 158 (64%) locoregional and 87 (36%) distant. Immediate RT significantly reduced the risk of relapse by 42% (HR=0.58 (95%CI: 0.45, 0.73), chi2LR=20.40, p<0.001) consistent across all prognostic subgroups. Immediate RT reduced the risk of locoregional relapse by 65% (HR=0.35 (95%CI: 0.25, 0.47), (chi2LR=40.47, p<0.001). No difference in relapse site, or frequency was seen between the 2 fractions. No differences were seen in overall or breast cancer specific survival.
 Discussion: With a median follow-up of 17 years, this study confirms the benefit for patients with early breast cancer receiving radiotherapy. We conclude that a radiotherapy schedule of 40 Gy in 15 daily fractions is a safe, efficient and effective regime at least as good as the international conventional regime of 50 Gy in 25 daily fractions. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5125.