De-escalation of Surgery for Occult Breast Cancer with Axillary Metastasis.

Occult breast cancer presenting as axillary metastasis is rare and remains a diagnostic and therapeutic challenge. Evidence to guide clinical management is limited, and locoregional treatment remains nonstandardized and highly varied nationally. Historically, occult breast cancer was managed with modified radical mastectomy ± radiotherapy; however, equivalent local control and survival are observed with breast preservation and adjuvant whole breast radiotherapy. Axillary lymph node dissection remains the standard surgical approach to the axilla for occult breast cancer patients. De-escalating axillary surgery in a subset of occult breast cancer patients treated with neoadjuvant chemotherapy with good response to treatment may be appropriate, similar to the management of clinically node-positive patients in a known primary setting. As in other clinically node-positive breast cancer cases, thoughtful integration and tailoring of axillary surgery and regional nodal radiotherapy (for the varying extent of nodal burden) is an area of continued controversy and active investigation.