Concurrent chemoradiotherapy using cisplatin and S-1, followed by surgery for stage II/IIIA non-small cell lung cancer

Objectives: Because chemoradiotherapy using cisplatin and S-1, an oral fluoropyrimidine, is effective for unresectable non-small cell lung cancer (NSCLC), an induction setting was used in a multicenter phase II study (Clinical trial number: UMIN000008205). The correlations of relapse and clinicopathological factors were analyzed. Methods: We defined locally advanced NSCLC as pathologically proven chest wall invasion or hilar and/or mediastinal lymph node metastases by endobronchial ultrasound-guided transbronchial needle aspiration. The patients received two courses of S-1 administration for 14 days and intravenous cisplatin injection on day 8. A total dose of 40 Gy radiotherapy was concurrently received. Surgical resection was performed after completion of the treatment. Results: Of the 23 eligible patients, 18 had stage IIIA and 5 had stage IIB NSCLC. Twenty of the eligible patients (87.0%) completed the regimen. Six (26.1%) complete responses were identified and 12 cases (52.2%) were histopathologically downstaged by induction chemoradiotherapy (ICRT). The 3-year overall survival rate was 58.1% and relapse-free survival (RFS) rate was 52.0%, respectively. Among several clinicopathological parameters, univariate RFS analysis identified that only downstaging was significantly associated with longer RFS times (p = 0.003). The radiological response did not reflect pathological response. When the variables of preoperative pathologically proven N2 metastasis, pathological ICRT effectiveness, and downstaging were included in the Cox proportional hazard modes, only the parameter of downstaging displayed significant hazard ratio (hazard ratio 0.13, p = 0.010). Conclusion: This protocol is considered an option among preoperative therapies and has obvious benefits for pathologically downstaged cases. Clinical trial number: UMIN000008205. Trial registration date: June 19, 2012.