Multicenter cohort study of impact of pathologic features of axillary soft tissue on breast cancer outcomes

In breast cancer, the current focus of axillary specimen pathology analysis is the tumor burden within the lymph node (LN) and extracapsular extension (ECE). No evidence defines the importance of tumor involvement within the axillary soft tissue (AXT) beyond the LN and ECE in predicting tumor outcomes and guiding treatment strategies. A cohort study of 2,162 LN+ breast cancer patients with median 9.4 years of follow-up showed that AXT involvement predicts worse tumor outcomes (locoregional failure, axillary failure, and distant metastasis). The authors conclude that routine reporting of AXT involvement, beyond LNs and ECE, is crucial in predicting breast cancer outcomes. Ruling out the presence of AXT involvement is imperative before any form of axillary de-escalation, especially omission of regional LN radiation.