Key clinical point: Patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (ERBB2−, aka HER2-) breast cancer (BC) experienced very low locoregional recurrence (LRR) events and comparable invasive disease-free survival (iDFS) outcomes both with and without receiving regional nodal irradiation (RNI) after surgery.
Major finding: The cumulative incidence of LRR at 5 years was low among patients who underwent breast-conserving surgery and radiotherapy with RNI (0.85%), breast-conserving surgery and radiotherapy without RNI (0.55%), mastectomy followed by radiotherapy (0.11%), or mastectomy without radiotherapy (1.7%). Receiving RNI was not associated with better iDFS outcomes (P > .1 for both pre- and postmenopausal women).
Study details: Findings are from the secondary analysis of the SWOG S1007 trial including 4871 women with HR+/ERBB2− node-positive BC, of whom 2274 women received RNI.
Disclosures: This study was supported by the US National Institutes of Health (NIH) and other sources. Some authors declared serving as consultants or receiving grants and personal fees from various sources, including NIH.
Source: Jagsi R et al. Radiotherapy use and incidence of locoregional recurrence in patients with favorable-risk, node-positive breast cancer enrolled in the SWOG S1007 trial. JAMA Oncol. 2023 (Jul 6). Doi: 10.1001/jamaoncol.2023.1984