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

ABSTRACT

AIMS: Postoperative radiotherapy is routinely used in early breast cancer employing either 50 Gy in 25 daily fractions (long course) or 40 Gy in 15 daily fractions (short course). The role of radiotherapy and shorter fractionation regimens require validation. MATERIALS AND METHODS: Patients with clinical stage I and II disease were randomised to receive immediate radiotherapy or delayed salvage treatment (no radiotherapy). Patients receiving radiotherapy were further randomised between long (50 Gy in 25 daily fractions) or short (40 Gy in 15 daily fractions) regimens. The primary outcome measure was time to first locoregional relapse. Reported results are at a median follow-up of 16.9 years (interquartile range 15.4-18.8). RESULTS: In total, 707 women were recruited between 1985 and 1992 median age 59 years (range 28-80), 68% postmenopausal, median tumour size 2.0 cm (range 0.12-8.0); 271 patients have relapsed 110 radiotherapy, 161 no radiotherapy. The site of first relapse was locoregional158 (64%) and distant 87 (36%). There was an estimated 24% reduction in the risk of any competing event (local relapse, distant relapse or death) with radiotherapy (hazard ratio = 0.76; 95% confidence interval 0.65, 0.88). The benefit of radiotherapy treatment for all competing event types was statistically significant (X(Wald)(2) = 36.04, P < 0.001). Immediate radiotherapy reduced the risk of locoregional relapse by 62% (hazard ratio = 0.38; 95% confidence interval 0.27, 0.53), consistent across prognostic subgroups. No differences were seen between either radiotherapy fractionation schedules. CONCLUSIONS: This study confirmed better locoregional control for patients with early breast cancer receiving radiotherapy. A radiotherapy schedule of 40 Gy in 15 daily fractions is an efficient and effective regimen that is at least as good as the international conventional regimen of 50 Gy in 25 daily fractions.