Abstract S5-07: SWOG S0500 – A randomized phase III trial to test the strategy of changing therapy versus maintaining therapy for metastatic breast cancer patients who have elevated circulating tumor cell (CTC) levels at first follow-up assessment

摘要: Introduction: CTC are detectable in approximately 75% of patients with metastatic breast cancer (MBC), and elevated (≥5CTC/7.5 ml whole blood (WB)) about half. Elevated at baseline associated a worse prognosis, decline levels suggests response to therapy. We initiated prospective randomized clinical trial (SWOG S0500) test whether change chemotherapy after failure clear one cycle first line would improve outcomes starting cytotoxic for MBC. Methods: Patients initiating first-line MBC were enrolled. All had measurable or evaluable disease that included bone metastases. who continued have 21 days therapy randomly assigned either continue initial until progression second (physician choice) immediately 2. baseline, which not the 21-day follow-up maintained on their without followed an observation arm. The primary endpoint was overall survival, progression-free survival secondary endpoint. It expected 500-650 be screened enroll 120 trial. Power 81% 2-sided α = 0.05 detect 70% increase median Three interim analyses planned during course Results: From 10/1/2006 3/15/2012, 624 registered whom 612 eligible. A obtained 593 (97%) eligible 317 (53%) baseline. Thirty-one (10%) did complete due death, progression, withdrawal, assay failure. Of 286 remaining patients, 123 (43%) CTCs maintain original (n 64) switched new 59). Final outcome results will analyzed October 2013 reported if released by SWOG Data Safety Monitoring Board. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S5-07.