[Introduction of studies by the German Breast Center Study Group (GBSG)]

The GBSG is actually running two studies on breast cancer therapy: GBSG-5 addresses the necessity of radiotherapy following tumor removal, in breast preserving treatment of pT1N0M0 G1 breast cancer. The other question to be answered in a randomised 2- by 2-design is related to the replacement of radiotherapy by a 5-year treatment with tamoxifen. Up till now, 341 patients have been randomised. 200 more patients are needed for a valid study evaluation. GBSG-6 will be activated in fall of this year. It should answer the question whether the addition of systemic therapy to the local treatment of isolated locoregional recurrence will prolong time to further relapse as well as overall survival. According to a prognostic profile derived drom previous studies patients will be randomly allocated to more or less intensive treatment with chemo- and/or hormone therapy.