Occult primary breast cancer at a comprehensive cancer center.

BACKGROUND: Management of occult primary breast cancer (OPBC), that is, breast cancer that first presents through regional nodal or distant disease without clinical or mammographic evidence of disease in the breast, has been controversial and inconsistent. Here, we review OPBC patients treated at our institution.
METHODS: We conducted a retrospective review of women diagnosed with a first primary breast cancer between March 1999 and September 2010 to identify patients who presented with isolated axillary lymphadenopathy proven to be histologically consistent with primary breast malignancy but had no evidence of a breast mass on physical examination, mammography, or ultrasound. Descriptions of treatments received, recurrence, morbidity, and mortality as of October 2012 are reported.
RESULTS: Of 5533 patients reviewed, seven (0.1%) patients were identified. The median age was 65 y old (range, 40-72), and the median length of follow-up was 86 mo (range, 42-124). Four patients underwent modified radical mastectomy, one patient had a lumpectomy and axillary lymph node dissection, and two patients had axillary lymph node dissection without breast surgery. Four patients received adjuvant radiation therapy. All seven patients received chemotherapy. Three patients received endocrine therapy, and two patients received anti-HER2 therapy. At the last follow-up, all seven patients were alive with no evidence of disease.
CONCLUSIONS: Although there was some variation in the management of OPBC at our institution, our patients had excellent outcomes after multimodal treatment. Our results support a curative intent approach to the treatment of OPBC and illustrate the need for individualized treatment algorithms based on tumor biology and extent of the disease at diagnosis.