Axillary Primary and Breast Cancer Management

Abstract

Axillary primary breast cancer, also known as occult primary breast cancer, is a rare entity representing less than 1% of all breast cancers. The surgical management of the axilla in breast cancer has changed significantly, with implications for the management of axillary primary breast cancer. Much of the data is limited by era, small cohorts, or large retrospective database studies. The purpose of this review is to reinforce the diagnostic work up of occult breast cancer, review updated management strategies of the axilla and breast, and summarize changes and updates in practice management and outcomes. Pathologic confirmation of breast primary disease and MRI are critical for the diagnostic work up of axillary primary breast cancer. A recent axillary primary specific meta-analyses and several National Cancer Database studies (NCDB) have reinforced that mastectomy versus breast conservation with whole breast radiation has equivalent outcomes. Surgical axillary management is under evolution, with multiple large trials reporting the role of neoadjuvant chemotherapy to downstage the node-positive axilla and decrease the morbidity of axillary lymph node dissection by allowing accurate sentinel node biopsy. Use of neoadjuvant chemotherapy and adjuvant radiation therapy is increasingly used, although no prospective data exists specifically in occult primary breast cancer. Appropriate diagnostic work up includes MRI to identify possible primary breast lesions in all patients with metastatic axillary disease and negative exam, mammography, and ultrasound. Axillary primary breast cancer should be treated with contemporary management strategies as other anatomic stage II breast cancers. Appropriate management strategies based on recent trial data suggest the use of neoadjuvant chemotherapy to downstage the axilla and allow for less morbid axillary surgery. Outcomes are equivalent with mastectomy or whole breast radiation.