Randomized trial on the effect of radiotherapy in addition to 6 cycles CMFin node-positive breast-cancer patients

In 1984 the GBSG started a multicenter randomized trial to compare the effe ctiveness of 6 cycles of cyclophosphamide, methotrexate and fluorouracil (C MF) with or without radiotherapy (RT) as adjuvant treatment in node positiv e breast-cancer patients treated by mastectomy, During 5 years, 199 patient s were randomized. After a median follow-up of about 9 years, the treatment groups 6 x CMF and 6 x CMF + RT were compared regarding time to recurrence and death, As the first event of failure, we observed locoregional recurre nce in 22 patients, distant metastases in 66 patients, a secondary malignan cy in 9 patients and death without previous event in 5 patients. For event free survival (EFS), no significant difference was observed [relative risk (RR) 6 x CMF + RT vs. 6 x CMF 0.82, 95% confidence interval (CI) 0.55-1.21] . Event-specific analysis showed a significant decreased risk after radioth erapy for locoregional recurrence, The risk for distant metastases was esti mated as slightly decreased and the risk for secondary malignancy and for d eath without previous event was estimated as increased in treatment group 6 x CMF + RT in comparison with treatment group 6 x CMF, but these effects w ere not significant. For overall survival (OS) and breast-cancer-specific s urvival (BCS), no significant treatment effect could be demonstrated. There is a beneficial effect of radiotherapy on locoregional recurrence, For EFS and BCS, a tendency in favour of radiotherapy is observed, but this is not significant; for OS, no difference can be demonstrated, but the power of t he study is too low to detect small treatment effects. Int. (C) 2000 Wiley- Liss, Inc.