Oncologic Outcomes with Neoadjuvant Chemotherapy and Breast Conservation for MRI Occult Breast Cancer

Background: Occult primary breast cancer is a presentation of breast cancerinvolving lymph nodes without an identified primary tumor within the breast.Mastectomy with axillary node dissection has been the traditional management.However, reported oncologic outcomes with mastectomy have been similar to thosewith breast conserving therapy (axillary surgery and radiotherapy). With theincreased sensitivity of MRI and its routine use in the workup of occult breastcancer, the role of mastectomy for occult breast cancer is now even less clear. Wereport our institutional experienc of neoadjuvant chemotherapy followed byaxillary surgery and radiotherapy for women with occult breast cancer. Methods: We conducted a retrospective review of women diagnosed withisolated metastatic adenocarcinoma to the axilla histologically consistent withbreast adenocarcinoma without evidence of a primary breast tumor. Medicalrecords were analyzed to gather pertinent information regarding diagnostic workup,treatment, recurrence, and survival. Results: We identified seven patients treated in our institution between ۲۰۱۲ and۲۰۱۷ who met the criteria for primary occult breast cancer. The median age atdiagnosis was ۶۳ years old (range ۴۲-۷۱). Subtypes by immunohistochemistry(IHC) were HER-۲ positive (۳ pts), triple negative (۲ pts), and hormone receptorpositive/HER-۲ negative (۲ pts). All patients received neoadjuvant chemotherapyand axillary surgery without mastectomy followed by adjuvant radiotherapy to thebreast and regional nodes. Hormone receptor positive patients received adjuvantendocrine therapy. At a median follow-up of ۳.۵ years, all patients were alive withno local or regional recurrence of disease while one patient developed distantmetastases. Conclusion: A multimodality approach with neoadjuvant chemotherapy canlead to high rates of breast conservation in women with primary occult breastcancer. This approach appears to be oncologically safe.

Keywords:

Occult primary breast cancer , axillary lymph node dissection , breast conservation