A phase II study of cisplatin (P), S-1 (S), and concurrent thoracic radiotherapy (TRT) for locally advanced non-small cell lung cancer (LA-NSCLC): Okayama Lung Cancer Study Group trial 0501.
7042 Background: We previously reported an efficacy and safety of fractionated schedule ofP and docetaxel (D) (days 1, 8, 29, and 36, each) and concurrent TRT (DP-TRT) for LA-NSCLC (JCO 2010). Although the median survival time (MST: 26.3 months) was excellent, grade 3 or greater pneumonitis (10%) and esophagitis (14%) were observed and treatment-related death was 3%.Thus, further improvement in the safety as well as efficacy is strongly warranted. S, an oral fluoropyrimidine, is a new active agent possessing a radio-sensitizing effect. Additionally, combining S and P offered an active and safe regimen for metastatic NSCLC. The objective of this study was to assess the efficacy and safety of S + P with concurrent TRT for LA-NSCLC. Methods: Patients with stage IIIA/IIIB, aged ≤75 years and PS 0-1, and without any prior chemotherapy were eligible for this study. Patients were treated with P (40 mg/m² on day 1, 8, 29 and 36) and S (40 mg/m²/dose b.i.d. on days 1-14 and 29-42) and TRT (60 Gy/30 fr over 6 weeks starting on day 1). Primary endpoint was response rate (RR), and required sample size was 48 patients. Results: Between 2006 and 2009, 48 patients were enrolled (37 men; median age, 66 years; PS 0/1, 36/14; IIIA/IIIB, 23/25; sq/non-sq, 22/26). Partial response was observed in 37 patients (77%; 95% confidence interval: 63-88%). The response rate was higher in older patients (≥65 yrs) than younger (<65 yrs) (89% vs. 64%, p=0.041). At a median follow-up of 40 months, median progression-free survival and MST were 9.3 months and 31.3 months, respectively. No difference in efficacy (response and survivals) was observed stratified by histology (sq vs. non-sq). Toxicities were generally mild, including G3/4 neutropenia (44%), G3/4 thrombocytopenia (13%), G3 febrile neutropenia (8%) and G3 pneumonitis (4%). No one developed Gr3/4 esophagitis. No toxic deaths occurred. Conclusions: This chemoradiotherapy regimen yielded a favorable overall survival data. Also, it was well-tolerated in patients with LA-NSCLC as compared with concurrent DP-TRT therapy especially in term of TRT-related toxicities. A phase III trial of this regimen vs. DP-TRT is now planned.