Controversies in Radiation Oncology for Early-Stage Breast Cancer

Multiple randomized trials, as well as a meta-analysis of these studies, have confirmed the equivalence of breast-conservation and mastectomy. In addition, in unselected populations, adjuvant radiation therapy following lumpectomy has been shown to decrease in-breast recurrence and improve overall survival. However, radiation has morbidity, and is costly and inconvenient. Multiple efforts to minimize treatment have been studied, including omitting radiation in low-risk populations, as well as in those with significant competing risks. Central to these efforts has been an increased awareness of the inherent biology, allowing treatment to be more precisely tailored to the risks posed by each individual patient's disease. In addition, an improved understanding of the radio-responsiveness of both tumor and adjacent normal tissue has permitted safe use of short-course (hypofractionated) radiation. Studies are ongoing to determine the most appropriate candidates for both hypofractionated treatment and omission of radiation entirely. The optimal management of ductal carcinoma in situ is also a subject of intense study. Multiple trials have attempted to identify patients who can safely forego radiation and, more recently, molecular predictors of recurrence have been developed to further fine-tune this low-risk population.