Clinical relevance of HER-2 expression in node-negative breast cancer patients

Abstract

598 Background: Adjuvant chemotherapy of node-negative breast cancer is generally being determined according to the St. Gallen classification. HER-2 expression, widely investigated in breast cancer but with controversy, is not a component of St. Gallen classification. This study was conducted to analyze clinical relevance of HER-2 expression in node-negative breast cancer. Methods: We retrospectively analyzed 906 node-negative breast cancer patients who were operated between 1995 and 2000. HER-2 protein overexpression was evaluated by immunohistochemistry. We grouped patients by tumor size (>2cm, ≤2cm), histologic grade (3, 1or2), age (<35yrs, ≥35yrs), ER status, PgR status and HER-2 expression. Then we analyzed prognostic value of these variables for disease-free survival (DFS) in all patients. In addition, prognostic value of HER-2 expression was analyzed in average/high risk group by St. Gallen classification. Results: In univariate analysis, tumor size, ER, PgR status, and HER-2 expression were prognostic factors for DFS. In multivariate analysis, only HER-2 expression was an independent prognostic factor for DFS. In average/high risk group by St. Gallen classification, HER-2 expression was a significant discriminant of prognosis. Data are summarized in the table below. Six-year relapse rate was 20.1% for HER-2 positive patients and 11.6% for HER-2 negative patients in average/high risk group. (P=0.0065). Conclusions: HER-2 expression was an independent prognostic factor for DFS in node-negative breast cancer. Furthermore, HER-2 expression in average/high risk group identified a subgroup of node-negative breast cancer patients with the worst prognosis, who were candidates for intensive adjuvant therapy. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Seoul National University Seoul National University