A combination of HER-2 status and the St. Gallen classification provides useful information on prognosis in lymph node-negative breast carcinoma

BACKGROUND. Adjuvant chemotherapy for patients with lymph node-negative breast carcinoma is being recommended currently based on the St. Gallen classification. The prognostic importance of HER-2 status in patients with lymph node-negative breast carcinoma has been investigated extensively, with contradictory results. The authors investigated the clinical relevance of HER-2 overexpression when combined with the St. Gallen classification in lymph node-negative breast carcinoma. METHODS. The medical records of patients with breast carcinoma negative for lymph node involvement who underwent surgery between January 1995 and December 2000 at the Seoul National University College of Medicine (Seoul, Korea) were reviewed retrospectively. Risk groups based on the St. Gallen classification were categorized as average or minimal risk. The prognostic values of HER-2 in combination with the St. Gallen classification were analyzed with respect to disease-free survival (DFS) rates. RESULTS. A total of 906 patients were eligible for analysis. The overall 7-year DFS rate was 87.5%. The 7-year DFS rates for patients with HER-2-positive and HER-2-negative tumors were, respectively, 77.9% and 91.2% (P = 0.002). The 7-year DFS rates for patients with average and minimal risk group were 85.0% and 97.9%, respectively. The authors found that HER-2 overexpression significantly predicted the risk of disease recurrence (odds ratio = 3.03 [95% confidence interval, 1.63 - 5.63]). Furthermore, when HER-2 status was combined with the St. Gallen classification, the DFS rate of the HER-2-positive average risk group was 73.3% compared with 88.4% for the HER-2-negative average risk group (P = 0.007). CONCLUSIONS. The combination of HER-2 overexpression and the St. Gallen classification was more useful than either alone to predict the risk of disease recurrence in patients with lymph node-negative breast carcinoma. (C) 2004 American Cancer Society.