7139 Background: The optimal combination of concomitant thoracic radiotherapy (TRT) and CT in stage III unresectable NSCLC remains unclear. The role of induction CT with Cb/G regimen, less toxic than Cisplatin/G, has not been established in stage III NSCLC. Methods: Forty-two patients (pts), 41 evaluable, entered this trial between January 2003 and November 2004, 27 males, 14 females, median age 60 (37–70), 19 pts with ECOG PS 0, 22 pts with PS 1, 22 pts with stage III A (N2), and 19 pts with stage III B (N2, N3). They received Cb AUC 5 i.v. on day 1 and G 1000 mg/m2 i.v. on days 1 + 8 every three weeks x 2 cycles, followed on day 50 by TRT, 60 Gy over 6 weeks, concomitantly with P 50 mg/m2 i.v. and G 100 mg/m2 i.v. on days 1 + 8 every three weeks x 2 cycles. Results: After induction CT, partial response (PR) was 73.1% (30 pts), stable disease (SD) 24.4% (10 pts), and 2.5% (1 pt) had progressive disease. After TRT and P/G, 19.5% (8 pts) had CR, 75.6% (31 pts) PR, and 4.9% (2 pts) PD. Median time-to-disease progression was 11.5 months. Median survival has not been reached yet, but surpassed 16.5 months; one-year survival is 71% (29 pts). Twenty three patients are still alive, after minimal follow-up of 13 months. First site of PD was in lungs in 7 pts, in brain 5 pts, in bones 4 pts; 2 pts died without PD, of cardiovascular disease. Toxicity of induction CT was minimal. During TRT and CT, grade 3 neutropenia, thrombocytopenia, and anemia occurred in 8 pts, 3 pts, and 3 pts respectively, grade 4 neutropenia and thrombocytopenia in one pt each. Nine pts received red cell transfusions, one pt platelet transfusion. One patient developed esophageal fistula with grade 4 toxicity, 3 pts had grade 3 esophagitis, 2 pts grade 3 infections, and one pt grade 3 dermatitis and elevation of liver enzymes. Conclusions: This regimen is effective, well tolerated, and appears to be an excellent choice for stage III NSCLC. Sponsored by Eli Lilly Canada. [Table: see text]