Pooled analysis of S-1 trials in non-small cell lung cancer according to histological type.

Background: The antimetabolic agent S-1 inhibits thymidylate synthase similar to pemetrexed, but through a different mechanism of action. Whether the antitumour activity of S-1 depends on histological type remains unclear. We analysed pooled data from 2 phase II clinical studies of cisplatin and S-I in patients with previously untreated advanced non-small cell lung cancer. Patients and Methods: We comprised 110 patients with stage IIIB or IV non small cell lung cancer. Univariate and multivariate analyses were performed to determine the effects of histological type on progression-free survival and response rates. Results: On pooled analysis of the data, according to histological type, median progression-free survival was 3.8 months in patients with squamous cell carcinoma and 4.4 months in those with non-squamous cell carcinoma. Both analyses showed that progression-free survival and response rate did not differ significantly. Conclusion: Unlike molecular targeted agents and pemetrexed, a combination of cisplatin and S-I may be no difference in response according to histological type.