Relationship between tumor characteristics and HER2/neu overexpression with response and outcome in locally advanced breast cancer (LABC) patients (pts) treated with neoadjuvant anthracycline-based chemotherapy (CHT)

Abstract

10698 Objectives: To retrospectively evaluate the relationship between HER2/neu status, pts’ characteristics, prognostic factors and clinical outcome in LABC women treated with neoadjuvant anthracycline-based CHT. Patients and Methods: 118 pts. with stage IIIA-B LABC, excluding inflammatory cancer, were included. HER2 overexpression was evaluated by immunohistochemistry (IHC), only IHC 3+ were defined as positive. The disease-free survival (DFS) was calculated according to Kaplan-Meier method. Fisher test, hazard ratios with 95% interval confidence, and Cox or Wilcoxon models were used. Kruskall-Wallis was used for comparison between medians. Results: Median age was 49 y (range: 31–69); 66 were pre-menopausal, 43 were stage IIIA and 77 IIIB; 59 pts. were N2. Primary tumor average size was 70 mm; 44 tumors were ER+, 43 PR+, 26 (22%) HER 3+, 104 histological grade III, 57 nuclear grade III. Seventy-four pts. (62.7%) achieved objective responses, with 7 complete clinical remissions. There was 1 progressive disease and only 3 pts. (2.5%) didn’t undertake mastectomy. After surgery, four pts. (3.5%) were evaluated as pathological complete remission, 6 (5.2%) with microscopic residual disease and 105 with macroscopic residual tumor. The median DFS was 19 months for the whole group and 39,6 and 31,6 for those achieving complete pathological remission and microscopic residual disease, respectively. There was no association between HER2/neu overexpression and pts’ characteristics, tumor prognostic factors nor with clinical or pathological responses. Negative PR, high tumor nuclear grade, clinical stage IIIA and complete clinical response were predictive factors for pathological response. In multivariate analysis, only pathological lymph node status was prognostic factor for DFS. Conclusions: There was no significant association between HER2 overexpression, tumor prognostic factors and clinical or pathological response to neoadjuvant CHT. Negative PR, high nuclear tumor grade, clinical stage IIIA and clinical complete response were associated to complete pathological response. Lymph node status was a strong prognostic factor for DFS. No significant financial relationships to disclose.