Therapeutic options for contralateral axillary lymph node metastasis in breast cancer

Contralateral axillary lymph node metastasis (CAM) in breast cancer is rare, and the reason is unclear. CAM may be found at the time of primary breast cancer diagnosis or following primary tumor treatment. CAM staging and treatment methods are controversial. Hence, we summarized the features of CAM patients and explored the therapeutic options. We report the case of an 82-year-old woman with right breast cancer accompanied by CAM. The records of breast cancer patients with CAM in PubMed (January 2000-May 2020) were also reviewed. After undergoing comprehensive treatments (neoadjuvant chemotherapy, surgery, radiotherapy, endocrine therapy, and targeted therapy), no signs of recurrence and metastasis were noted during the 25-month follow-up. Overall, 17 studies (36 patients) were selected for the review, of which 15 had synchronous CAM and 21 had metachronous CAM. Nineteen of 22 patients had histologic grade 3. Forty percent (12/30) had ≥4 positive lymph nodes. Among these 36 patients, 9 had triple-negative breast cancers, and 9 were human epidermal growth factor receptor 2 positive. Among the 30 patients staged, 6 (20%) were in stage I; 7 (23.33%), stage II; and 17 (56.67%), stage III. Two patients received systemic therapy, while one received an unknown treatment. The remaining 33 patients all received local treatment (surgery or radiotherapy). The survival time of synchronous and metachronous CAM patients was 12-72 months with the death rate of 1/7 and 12-144 months with that of 3/12, respectively. CAM may be a regional manifestation rather than a distant metastasis. Comprehensive treatment, including surgery and radiotherapy, may provide better control.