C-erbB-2 Expression Predicts Tamoxifen Efficacy in Breast Cancer Patients

ABSTRACT

PURPOSE: It has been reported that c-erbB-2 overexpression is associated with a resistance to tamoxifen therapy in many trials, but this is controversial. The aim of this study was to evaluate the c-erbB-2 status, and the response to tamoxifen, in breast cancer patients. METHODS: We enrolled 294 patients who had been treated with tamoxifen, 261 (88.8%) were ER and 33 PR positive respectively. The expressions of c-erbB-2 were analyzed using immunohistochemical methods. The median follow up was 36 months. We medical records retrospectively reviewed, and the recurrence rate analyzed and compared with other prognostic factors and survival rates, according to the c-erbB-2 status. RESULTS: The mean age of the patients was 45.23+/-10.47 (20~83). The incidence of invasive ductal carcinomas, invasive lobular carcinomas and DCIS were 91.2, 4.8 and 4.1%, respectively. The recurrence rate was 10.9% (32/294), and 22 of 225 (9.8%) in ER/PR (+/+), 7 of 36 (19.4%) in ER/PR (+/-) and 3 of 33 (9.1%) in ER/PR (-/+). The recurrence rates, according to the TNM stages 0, I, IIa, IIb, III were 0, 5.4, 6.5, 15.2 and 36.7%, respectively (P=0.000). The recurrence rates, according to the c-erbB-2 stati, were 16.5 and 8.4% in the positive and negative groups, respecively (P=0.039). The nuclear grade was higher in the c-erbB-2 positive group than in the negative group, but there was no relationship between the c-erbB-2 status and the other prognostic factors, such as axillary lymph node status, TNM stage or histological grade. The overall and disease free survivals were significantly shorter in the c-erbB-2 positive than the negative group (P<0.05). CONCLUSION: The patients with tumors positive for c-erbB-2 had shorter overall and disease free survivals, compared to patients with tumors negative for c-erbB-2, when treated with tamoxifen. Overexpression of c-erbB-2 may reduce the efficacy of tamoxifen therapy, although our number of patients was small and the follow up relatively short.