Pathologic Findings of Residual Tumor according to the Response Rate after Neoadjuvant Chemotherapy for Breast Cancer

ABSTRACT

PURPOSE: There are questions about selecting the best postoperative chemotherapeutic regimen for breast cancer patients who have different response rates after neoadjuvant chemotherapy. The aim of this study was to examine the pathologic findings of residual tumors according to the response rate after neoadjuvant chemotherapy for breast cancer. METHODS: We obtained specimens of residual tumors from 43 breast cancer patients who received neoadjuvant chemotherapy followed by curative operation at the Department of Breast and Endocrine Surgery, Sacred Heart Hospital, between Oct. 2002 and Oct. 2006. Four patients received 3 cycles of FAC (5-FU, Adriamycin, Cyclophosphamide) and 39 patients received 3 cycles of AT (Adriamycin, Docetaxel). We analyzed the pathologic characteristics according to the response rate. RESULTS: The clinical response rate for neoadjuvant chemotherapy was 69.8%. There was no significant difference in the response rate for neoadjuvant chemotherapy between the AT and the FAC regimen groups. The tumors of the complete response group showed to be more ER-negative, PR-positive, p53-negative and c-erb-B2-positive and they had a lower Ki-67 staining index than the tumors of the partial response group. Moreover, the tumors of the clinical complete response group showed more triple (ER/PR/c-erb-B2) negative tumor than did the tumors of the partial response group. CONCLUSION: Although the tumor responded to neoadjuvant chemotherapy, the pathologic findings of the residual tumors in the clinical complete response group differed from that of the partial response group. So, this should be considered for the selection of postoperative chemotherapeutic agents.