[Four Cases of Occult Breast Cancer Treated with Breast Conserving Therapy after Neoadjuvant Chemotherapy]

We report 4 patients with occult breast cancer(OBC)who underwent breast conserving therapy(BCT)after neoadjuvant chemotherapy(NAC). All patients complained of axillary tumor and were diagnosed by core needle biopsy. Pathological examination of the axillary lymph nodes proved that 3 cases were adenocarcinomas and 1 case was squamous cell carcinoma, but imaging studies could not depict any primary lesions in the breast and other organs. Since distant metastasis was not observed, BCT with axillary lymph node dissection(ALND)was performed after NAC. All patients were undergoing whole breast irradiation. There were no residual cancer cells in the axillary lymph nodes in case 1 due to the treatment effect of NAC, but lymph node metastasis remained in other 3 cases. In the second case, she followed a rapid outcome, and pulmonary metastasis appeared in 7 months after surgery and died in 10 months. In the other 3 cases, there has not been found local and distant recurrence. Although OBC requires appropriate systemic treatment, present observation indicated that ALND with breast irradiation after NAC could be a useful option.