Abstract CS1-3: Contemporary role of radiotherapy in axillary management

Abstract

Abstract Sentinel lymph node evaluation is an innovation that has radically transformed the surgical approach to the axilla in many patients with breast cancer. This revolution in surgical management has important implications for the optimal use of radiotherapy. The context of decision-making has changed dramatically with the recent maturation of studies that have demonstrated low rates of axillary failure in select patients with clinically negative axillae and 1-2 nodes positive on sentinel node biopsy, even without completion axillary dissection. Optimizing the radiotherapeutic management of the axilla in this modern context requires sophisticated understanding of the characteristics of patients who enrolled on trials such as ACOSOG Z0011 and IBSCG 23-01, including their risk factors and systemic management, as well as the radiation fields actually treated. Many patients treated on these trials received substantial incidental radiation to axillary levels I and II from tangential radiotherapy fields, and some even received directed nodal irradiation, but others did well with little or no radiation at all to the axilla. Understanding how to apply the results of these trials to guide current practice requires the radiation oncologist to integrate the insights of these studies with those from other recent studies evaluating the role of more comprehensive regional nodal radiotherapy that included the supraclavicular and internal mammary regions. Recognizing how the patient populations treated on the NCIC MA20 and EORTC 22922 trials may have differed from those on ACOSOG Z0011 and IBSCG 23-01 is necessary to help reconcile the findings of these studies and guide us in optimizing our patients' radiotherapeutic management decisions. In addition, the landmark AMAROS study, in which patients with clinically negative axillae were randomized to axillary dissection versus axillary radiation after a positive sentinel node biopsy, adds to a long history of clinical trials evaluating the question of optimal axillary management. These studies must be considered in detail in order to determine how best to individualize the use of radiation therapy to maximize disease control and minimize treatment-related morbidity. These issues will be the focus of this clinical science symposium lecture, which will provide a radiation oncologist's perspective on regional nodal management for patients diagnosed with invasive breast cancer, with a specific focus on the axilla. Citation Format: Jagsi R. Contemporary role of radiotherapy in axillary management. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr CS1-3.