HER-2/neu overexpression as a poor prognostic factor for patients with metastatic breast cancer undergoing high-dose chemotherapy with autologous stem cell transplantation.

PURPOSE High-dose chemotherapy with autologous stem cell transplantation (HDCT) produces a high tumor response rate for patients with metastatic breast cancer and have 20% long-term progression-free survival. Overexpression of HER-2/neu oncoprotein predicts outcome in patients with breast cancer given standard-dose chemotherapy. Therefore, we evaluated whether the HER-2/neu overexpression in the primary tumor predicts clinical outcome in patients with metastatic breast cancer given HDCT. EXPERIMENTAL DESIGN A total of 236 patients were given standard-dose induction chemotherapy followed by stem cell collection; high-dose chemotherapy with cyclophosphamide, thiotepa, and carmustine; and stem cell infusion. HER-2/neu expression was assessed by immunostaining with anti-HER-2/neu e2-4001 monoclonal antibody in 63 patients. RESULTS Clinical characteristics and survival were similar for patients with known and unknown HER-2/neu status. HER-2/neu was overexpressed in 22 of 63 tumors (35%). There was some tendency for HER-2/neu overexpression to be associated with the absence of estrogen or progesterone receptors. In considering the association of HER-2/neu expression with patient outcomes, HER-2/neu overexpression was associated with generally shorter overall survival (P = 0.02) and progression-free survival (P < 0.01), and this association persisted to a lesser extent after adjustment for differences in important prognostic factors between the two groups. CONCLUSION We conclude that HER-2/neu overexpression may represent an additional prognostic factor for patients with metastatic breast cancer who undergo HDCT.