Carboplatin, S-1 and concurrent thoracic radiotherapy for elderly patients with locally advanced non-small cell lung cancer: a multicenter Phase I/II study

Objectives We conducted a Phase I/II study of carboplatin, S-1 and concurrent thoracic radiotherapy (TRT) for elderly patients (71 years or older) with unresectable stage III non-small cell lung cancer (NSCLC). Materials and methods Patients received carboplatin (AUC 3-5) on Day 1 and S-1 (30–40 mg/m2 two times daily) on Days 1–14, every 2 weeks, for up to four cycles, plus concurrent TRT at a total dose of 60 Gy. The primary endpoint for the Phase II study was the 1-year progression-free survival (PFS) rate. Results Eighteen patients were enrolled in the Phase I study. Febrile neutropenia, a decreased platelet count and esophagitis were dose-limiting toxicities. The recommended doses for the Phase II study were determined to be an AUC of 3 for carboplatin, 40 mg/m2 twice daily for S-1. Twenty-eight patients were evaluated in the Phase II study. The 1-year PFS rate was 57.1% (90% CI 41.6–71.4%), and the median PFS was 16.8 months (95% CI 7.8–not assessable [NA]). The lower limit of the 90% CI for 1-year PFS exceeded the prespecified threshold value of 30%; therefore, the primary endpoint was met. Grades 3–4 toxicities included thrombocytopenia (21%) and hyponatremia (11%). Grade 3 radiation pneumonitis was observed in 18% of patients. No treatment-related deaths were observed. Conclusion Combination chemotherapy consisting of carboplatin plus S-1 and concurrent TRT had a promising efficacy in elderly patients with locally advanced NSCLC; however, radiation pneumonitis was frequently observed.