Editorial: New Approaches to Breast Cancer Radiotherapy

Abstract

Multiple randomized clinical trials have confirmed the efficacy of radiation therapy in reducing local recurrence of breast cancer (1). For decades the predominant approach was six weeks of whole breast radiotherapy followed by a boost. This “one size fits all” paradigm has been questioned based on the identification of molecular markers, genomic profiling, and other prognostic factors that indicate recurrence risk for individual patients. Breast cancer survival has improved in developed countries with almost 80% of patients surviving at least 10 years. Long-term survival reveals the late toxicity of all treatment modalities and provides an incentive to develop effective treatments that maintain quality of life. In the field of radiation oncology, we have the opportunity to tailor our treatments for each patient to improve progression free survival, minimize normal tissue toxicity and functional impairment, and respect our patient’s resources and time constraints. We have seen a de-escalation of the surgical approach to breast cancer and the development of a more personalized targeted approach to the selection of systemic therapy. Technical innovations in radiotherapy delivery provide the opportunity to treat patients with greater precision and fewer treatments. Radiation delivery can be modified by altering volume, dose, timing, number and overall duration of treatment consistent with optimal medical outcome and quality of life. Hypofractionation, which reduces the number and overall treatment duration, has become the recommended approach to whole breast RT (2, 3). The concept of APBI (accelerated partial breast irradiation) which minimizes volume, treatment number and duration, has been demonstrated to be appropriate for low-risk patients (4–7). Clinical trials have explored more efficient fractionation for whole breast RT (8, 9) and novel approaches to APBI. Technical progress in radiation image guidance, planning, and treatment delivery has fostered the development of SBRT (stereotactic body radiotherapy) and stereotactic ablative radiotherapy (SABR) as an ablative treatment for primary and metastatic cancer. In this Research Topic, New Approaches to Breast Cancer Radiotherapy, we have included original research and review articles that describe SBRT for primary and metastatic breast cancer, MR-guided RT for neoadjuvant local treatment, aggressive local management of breast cancer with synchronous metastases, and a new look at the breast boost. The article by Lee et al. describes the first experience in Korea of stereotactic partial breast irradiation. While accelerated partial breast irradiation (APBI) has been demonstrated in randomized trials to be non-inferior to whole breast radiation in selected patients with low-risk