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

Background: Recent publications of the Danish Breast Cancer Cooperative Gro up together with data from the British Columbia Trial have stirred major di scussions concerning the role of radiation therapy after mastectomy, Differ ent treatment approaches are to be found even within the same cancer center . The German Society of Senology, a cooperative group of all medical discip lines involved in the treatment of breast cancer, 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 investigatio ns with regard to the time course of distant metastases in breast cancer as well as the current consensus of the American Society for Therapeutic Radi ology 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 (RO) resection of the tumor as well a s dissection of at Least 10 Lymph nodes from the axillary Level I and II sh ould be accomplished. If axillary Lymph nodes are involved, the surgical re moval of these lymph nodes is not only of diagnostic, but also of therapeut ic value, as it reduces the risk for Locoregional relapses. (2) Most probab ly, Locoregional relapses do not only indicate, but are also a source for d istant metastases. (3) Radiation therapy of the chest wall and the regional Lymph nodes increases the overall survival in risk patients and reduces th e risk of Locoregional relapses. Moreover, radiation therapy improves the p rognosis in case of residual tumor or an incomplete axillary dissection. Un equivocal and reasonable indications for radiation therapy after mastectomy include T3/T4-carcinoma, T2-carcinoma >3 cm, multicentric tumor growth, ly mphangiosis carcinomatosa or vessel involvement, involvement of the pectora lis fascia or a safety margin <5 mm, R1- or R2 resection and more than 3 ax illary Lymph node metastases. Further reasonable indications, albeit not ye t evaluated in clinical trials, include multifocality, extensive intraducta l component, negative hormone receptor status, G3-differentiation grade, di ffuse micro-calcifications 1 to 3 axillary Lymph node metastases, multiple, non-complete biopsies and age <35 years. (4) An endocrine therapy with tam oxifen concurrent to radiation therapy is also reasonable - despite some co ntradictory in-vitro data - as it enhances the apoptotic cell death. The CM F-regimen is usually performed as sandwich procedure, but can also be appl ied concurrently to radiation therapy, if indicated. Conversely, an anthrac ycline-containing chemotherapy should be finished prior to postoperative ra diation therapy. Conclusions: Adjuvant radiation therapy after mastectomy improves the 10-ye ar-survival probability up to 10%, at Least for risk patients. The hypothes es of Halsted and Fisher do not exclude each other. There are patients, in which the one, and there are patients, in which the other hypothesis applie s.