Her-2/neu expression as a predictive factor for response to anthracycline-based chemotherapy in a mexican population of locally advanced breast cancer patients.

Breast cancer is the second most frequent tumor in Mexico 30-50% are diagnosed in locally advanced stages requiring neoadjuvant chemotherapy. The overexpression of HER-2/neu has been identified as a chemotherapy response predictor. The objective of our study was to identify response predictive factors to anthracycline-based neoadjuvant chemotherapy in locally advanced breast cancer. Data were collected from clinical records of patients with neoadjuvant anthracycline-based chemotherapy, for clinical stage III breast cancer from 1992 to 1997. Paraffin blocks were reviewed to determine histologic grade, HER-2/neu expression, and ploidy. Patients were divided in two groups: A, 56 cases responding to chemotherapy and, B, 20 nonresponders. Mean age was 50.1 and 45.4 for groups A and B, respectively (OR 7.02, p = 0.004), and those premenopausal were 43% and 70%, respectively (OR 3.1, p = 0.04). Mean tumor size was 5 cm in responders and 8 cm for nonresponders (OR 4, p = 0.02). Clinical stage III-B 16% and 70% for groups A and B (OR 12.2, p = 0.000); tumors were aneuploid in 39% of responders and 18.7% for nonresponders. HER-2 /neu was overexpressed in 64.2% and 50% for groups A and B (OR 3.6, p = 0.06). On multivariate analysis significance was conserved only for age, clinical stage, and size. HER-2/neu lost significance. Age and size were importantly related to tumor response, a higher percentage of HER-2/neu overexpression was observed in responders, without significance due to small sample size. It would be important to study a larger number of patients to obtain more conclusive results.