A phase I study of S-1 with concurrent radiotherapy in elderly patients with locally advanced non-small cell lung cancer

Background A phase I study was performed to evaluate dose-limiting toxicity and the recommended dose for the oral fluoropyrimidine S-1 administered concurrently with thoracic radiotherapy (TRT) in elderly (≥70 years of age) patients with locally advanced non-small cell lung cancer. Methods S-1 was administered on days 1 to 14 and 22 to 35 at oral doses of 65 or 80 mg m−2 day−1. TRT was administered in 2-Gy fractions five times weekly for a total dose of 60 Gy. Twelve previously untreated patients were treated with S-1 at 65 (n = 6) or 80 (n = 6) mg m−2 day−1. Results All patients completed the planned 60 Gy of TRT. Dose-limiting toxicity included pneumonitis (n = 2), infection (n = 1), and stomatitis (n = 1), each of grade 3, but each event was reversible. The recommended dose for S-1 was determined to be 80 mg m−2 day−1. No patient experienced toxicity of grade 4. The dose intensity of S-1 was well maintained and the combination of S-1 plus TRT was well tolerated overall. The overall response rate was 83.3 %, with a median survival time of 34.0 months. Conclusions Administration of S-1 at 80 mg m−2 day−1 on days 1 to 14 and 22 to 35 can be safely combined with concurrent TRT in elderly patients with locally advanced non-small cell lung cancer.