Effects of different chemotherapy regimens and tamoxifen for HER2 over-expressed breast cancer adjuvant therapy

Abstract

11048 Background: To evaluate effects of different adjuvant chemotherapy regimens and TAM in HER-2-overexpressed breast cancer patients. Methods: To study 1625 primary breast cancer cases after operation from 2002.7 to 2005.11 given adjuvant chemotherapy ,600 cases given CMF, 600 cases given CEF, and 425 cases given T-regimen (anthracyclines follow taxanes),1090 HR+ cases given tamoxifen. HER-2 expression were measured by immunohistochemistry (IHC). Median follow-up time is 42 months. Results: (1)3yr DFS of HER-2 over-expression is inferior to HER-2 negative ones in CMF group(p<0.05), no difference between HER-2- overexpressed and HER-2-negative group treated with either CEF or taxanes-based regimen (p>0.05). Subgroup analysis suggested: patients treated with CMF, 3yr DFS of HER-2 over-expression is inferior to HER-2-negative ones in node-positive subgroup, but no difference in node-negative ones; HER-2 expression has no influence on effects of CEF or T-regimen in node-positive or node-negative subgroup. (2) 425 HER-2 over-expressed patients(183 cases given CMF , 121 cases given CEF , and 121 cases given T-regimen): compared to CMF, anthracyclines and taxanes are more effective, but no difference between anthracyclines and T-regimen. (3) 235 patients with HER-2 over- expression and node-postive (72 cases given CMF , 68 cases given CEF, and 95 cases given T-regimen):, anthracyclines and taxanes are more effective than CMF, but no difference between anthracyclines and T-regimen. (4)3yr DFS is 91.23% in HER-2 over-expressed group and 93.42% in HER-2-negative group (p=0.04) with TAM. HER-2 over-expressed patients are resistant to TAM. (5) Subgroup analysis suggested that: 3yr DFS is 88.67% with HER-2 over-expression and 92.20% with HER-2-negative in postmenopausal node-positive subgroup(p=0.0069), postmenopausal patients with HER-2 over-expression and node-positve are resistant to TAM; no difference in either premenopausal or postmenopausal node-negative subgroup (p>0.05). Conclusions: No difference between Anthracyclines based and T-regimens for HER2 over-expressed patients with node-positive for 3yr DFS.Postmenopausal ER+/PR+ patients with HER2 over- expression are resistant to Tamoxifen endocrine therapy. No significant financial relationships to disclose.