Final 10-year analysis of prospective multicenter Chemo N0 trial for validation of ASCO-recommended biomarkers uPA/PAI-1 for therapy decision making in node-negative breast cancer

511 Background: Based on interim results of the prospective, randomized, multicenter Chemo N0 trial and an EORTC pooled analysis (n = 8,377), ASCO and AGO guidelines recommend invasion markers uPA/PAI-1 for risk assessment in N0 breast cancer. Methods: We present final analysis of the Chemo N0 trial (recruitment 1993–1998; n = 647; 12 centers) with 113 (5–167) months median follow-up. Patients (pts) with low tumor levels of uPA and PAI-1 (n = 283) were observed. Of 364 patients with high uPA and/or PAI-1, 242 were randomized to CMF chemotherapy (n = 117) vs. observation (n =125); 122 pts decided for or against CMF on their own. External quality assurance provided good ELISA standardization in 5 participating laboratories. Results: The actuarial 10-year recurrence rate (without any adjuvant systemic therapy) for high uPA/PAI-1 pts in the combined (randomized and not randomized) observation group was 23.0%, in contrast to only 12.9% in those with low uPA/PAI-1 (p = 0.011, log rank). High-risk pts randomized...