S-1 + Cisplatin with Concurrent Radiotherapy Followed by Surgery for Stage IIIA (N2) Lung Squamous Cell Carcinoma: Results of a Phase II Trial.

Abstract

To date, no clinical trials on the use of induction therapy before surgery have focused solely on lung squamous cell carcinoma (LSCC). We report the results of the Personalized Induction Therapy-2 (PIT-2) trial, a multicenter phase II study, performed to investigate the efficacy and safety of S-1 + cisplatin with concurrent thoracic radiotherapy (TRT) followed by surgery in patients with stage IIIA (N2) LSCC. Patients with pathologically proven stage IIIA (N2) LSCC received induction therapy comprising three cycles of S-1 + cisplatin with concurrent TRT (45 Gy in 25 fractions) followed by surgery. S-1 was administered orally at a dose of 40mg/m2 twice daily on days 1-14, in addition to intravenous infusion of cisplatin (60mg/m2) on day 1. The primary endpoint was 2-year progression-free survival (PFS) rate. Of 45 registered patients, 43 underwent induction therapy. Of the 43 patients, 39 (91%) underwent surgery (35 lobectomies, 3 pneumonectomies, and 1 wedge resection). The 2-year PFS, 2-year overall survival, objective response rate, and pathological complete response rates were 67% (90% confidence interval [CI] 54-78%), 70% (95% CI 53-81%), 86% (95% CI 76-96%), and 39% (95% CI 23-54%), respectively. No new treatment-related adverse events occurred during the induction therapy. One case of 90-day postoperative mortality involving a patient who underwent right pneumonectomy and developed pneumonia after discharge occurred. Induction therapy using S-1 + cisplatin with concurrent TRT followed by surgery is a feasible and promising treatment approach for stage IIIA (N2) LSCC.