Irinotecan plus cisplatin shows no RFS benefit over etoposide plus cisplatin in resected lung HGNEC

INTRODUCTION: We aimed to evaluate the long-term follow-up overall survival (OS) of irinotecan plus cisplatin (IP) versus etoposide plus cisplatin (EP) as postoperative adjuvant chemotherapy in patients with pathological Stage I-IIIA high-grade neuroendocrine carcinoma (HGNEC) of the lung. METHODS: The JCOG1205/1206 randomized, open-label, phase III study compared the efficacy of IP and EP as adjuvant chemotherapy. Patients with pathological Stage I-IIIA and completely resected HGNEC of the lung were randomized to receive either the IP or EP arm. The primary endpoint was relapse-free survival (RFS), and the secondary endpoint included overall survival (OS). The analyses were performed using data from 5 years after the last patient enrollment. In addition, a central pathological review was planned for this study. RESULTS: Between April 2013 and October 2018, 221 patients were enrolled (EP arm, 111 patients; IP arm, 110 patients). Updated respective 3- and 5-year RFS rates were 68.5% and 65.7% in the EP arm versus 71.8% and 65.2% in the IP arm, with a hazard ratio (HR) of 1.026 (95% confidence interval [CI], 0.670-1.569). OS at 3 and 5 years was 85.6% and 73.5%, respectively, in the EP arm versus 83.6% and 72.4%, respectively, in the IP arm (HR, 1.175; 95% CI, 0.742-1.861). The concordance proportion of pathological diagnoses between each institution and central pathological reviews was 75.6% (95% CI, 69.4%-81.1%). CONCLUSIONS: Our results showed no significant difference in both updated RFS and OS between the two arms for patients with completely resected HGNEC.