Postmastectomy Radiotherapy Decision for Patients without Lymph Node Metastases: Turkish Radiation Oncology Society Breast Cancer Working Group

Abstract

OBJECTIVE Recent meta-analysis have not revealed any positive effects of postmastectomy radiotherapy (PMRT) on locoregional recurrence (LRR) or overall survival in axilla-negative patients. However, risk of LRR increases to 15% in the presence of two or more adverse factors for the same patient group. In this study, PMRT indications and volume selections of radiation oncologists in Turkey for axilla-negative breast cancer was investigated. METHODS Questionnaires were distributed to members of the breast cancer study group. Data of patients with axillary negative or isolated/micrometastasis and PMRT over 10 years (2006-2016) were collected from 10 participating centers. Clinical and tumor histopathological features and treatment details of 185 patients were analyzed. RESULTS The median age of patients was 48 years. Ratio of early-stage patients was 60% (T1-15%,T2-45%). There were 147 (79%) negative cases, 32 (17%) with micrometastasis, and 6 (3%) with isolated tumor cells. Half of the patients had only their chest walls (CW) irradiated. Peripheral lymphatics were also included in the rest. In Nmic cases, ratio of irradiation of supraclavicular and axillary lymph nodes with CW were statistically significant compared to CW irradiation (72% and 28%, respectively; p=0.015). CONCLUSION Considering the low number of patients treated over 10 years in 10 different centers in Turkey, it can be said that PMRT is often done in node-negative breast cancer. It is difficult to reach a definite conclusion for patients with Nmic, due to lack of data from patients with PMRT. However, the general tendency is to irradiate peripheral lymphatics in Nmic cases if PMRT is to be performed.