Pathologic Features of Breast Cancer Associated with Complete Response to Neoadjuvant Chemotherapy: Importance of Tumor Necrosis

Breast cancer patients with a complete pathologic response after neoadjuvant chemotherapy have a better prognosis than incomplete responders. The predictive value of the histologic characteristics of the tumor prior to neoadjuvant treatment has not been well defined, and there are no guidelines for reporting tumor characteristics in the core biopsy report. Histologic and nuclear grades, presence of tumor necrosis and angiolymphatic invasion (ALI), and estrogen receptor (ER), progesterone receptor (PR), and HER-2/neu expression were assessed in core biopsies of 55 patients with invasive carcinomas. Patients were then uniformly treated with four cycles of doxorubicin/docetaxel followed by excisions and lymph node dissections. Complete pathologic response (pCR) was defined as having no invasive carcinoma at excision. Noncomplete pathologic response was defined as having invasive carcinoma at excision. Five of the 55 patients (9%) achieved pCR. Of the 5 complete responders, 4 (80%) had tumor necrosis in the core biopsy specimens, while only 8 of the 46 (17%) noncomplete responders (pNR) had this feature (P = 0.0086). Higher histologic and nuclear grades, ER, PR status, and HER-2/neu overexpression were not associated with pCR. The presence of ALI in the core biopsy, post-therapy excision, or both was associated with axillary lymph node metastases (P = 0.0062, P = 0.0249, and P = 0.0021, respectively). Although preliminary, our study suggests that the presence of tumor necrosis and ALI in the core biopsy may be important features to be included in the standard report.