Radiation therapy after mastectomy. Interdisciplinary consensus puts an end to a controversy

The German Society of Senology has therefore worked out a consensus statement. Material and Method: The recently published literature and experts opinions, in particular randomized studies since 1997, meta-analyses from the Early Breast Cancer Trialists' Collaborative Group, epidemiological investigations with regard to the time course of distant metastases in breast cancer as well as the current consensus of the American Society for Therapeutic Radiology and Oncology served as the basis for discussion and consulting. Results of the Consensus: (1) An optimally performed mastectomy is a major prerequisite for tumor cure. Radical (R0) resection of the tumor as well as dissection of at least 10 lymph nodes from the axillary level I and II should be accomplished. If axillary lymph nodes are involved, the surgical removal of these lymph nodes is not only of diagnostic, but also of therapeutic value, as it reduces the risk for locoregional relapses. (2) Most probably, locoregional relapses do not only indicate, but are also a source for distant metastases. (3) Radiation therapy of the chest wall and the regional lymph nodes increases the overall survival in risk patients and reduces the risk of locoregional relapses. Moreover, radiation therapy improves the prognosis in case of residual tumor or an incomplete axillary dissection. Unequivocal and reasonable indications for radiation therapy after mastectomy include T3/T4-carcinoma, T2-carcinoma>3 cm, multicentric tumor growth, lymphangiosis carcinomatosa or vessel involvement, involvement of the pectoralis fascia or a safety margin<5 mm, R1- or R2 resection and more than 3 axillary lymph node metastases. Further reasonable indications, albeit not yet evaluated in clinical trials, include multifocality, extensive intraductal component, negative hormone receptor status, G3-differentiation grade, diffuse micro-calcifications, 1 to 3 axillary lymph node metastases, multiple, non-complete biopsies and age<35 years. (4) An endocrine therapy with tamoxifen concurrent to radiation therapy is also reasonable - despite some contradictory in-vitro data - as it enhances the apoptotic cell death. The CMF-regimen is usually performed as sandwich procedure, but can also be applied concurrently to radiation therapy, if indicated. Conversely, an anthracycline-containing chemotherapy should be finished prior to postoperative radiation therapy. Conclusions: Adjuvant radiation therapy after mastectomy improves the 10-year-survival probability up to 10%, at least for risk patients. (orig.)