Feasibility of breast preservation in the treatment of occult primary carcinoma presenting with axillary metastases

Background: The objective of the study was to compare the treatment outcomes in patients with occult primary carcinoma with axillary lymph node metastasis who were treated with mastectomy or with intent to preserve the breast. Methods: From 1951 to 1998, 479 female patients were registered with axillary lymph node metastasis from an unknown primary. After clinical workup, including mammography, 45 patients retained this diagnosis and received treatment for T0 N1-2 M0 carcinoma of the breast. Clinical and pathological data were collected retrospectively, and survival was calculated from the date of initial diagnosis using the Kaplan-Meier method. Median follow-up time was 7 years. Results: Median age was 54 years (range, 32-79). Clinical nodal status was N1 in 71% and N2 in 29% of the patients. Surgical treatment was mastectomy in 29% and an intent to preserve the breast in 71% of the patients. Locoregional radiotherapy was used in 71% and systemic chemoendocrine therapy was used in 73% of the patients. Of the 13 mastectomy patients, only one had a primary tumor discovered in the specimen. Two patients (4%) were ultimately diagnosed with lung cancer and neuroendocrine tumor. No significant difference was detected between mastectomy and breast preservation in locoregional recurrence (15% versus 13%), distant metastases (31% versus 22%), or 5-year survival (75% vs. 79%). Regardless of surgical therapy, the most important determinant of survival was the number of positive nodes. Five-year overall survival was 87% with 1-3 positive nodes compared with 42% with ≥4 positive nodes (P < .0001). Conclusions: Occult primary carcinoma with axillary metastases can be treated with preservation of the breast without a negative impact on local control or survival.