Association of Chemoradiotherapy With Outcomes Among Patients With Stage I to II vs Stage III Small Cell Lung Cancer

Abstract

Importance: There is limited evidence to guide stage I to II small cell lung cancer (SCLC) treatment. Objective: To examine the characteristics and outcomes among patients with stage I to II SCLC treated with modern chemoradiotherapy. Design, Setting, and Participants: In this post hoc secondary analysis of the Concurrent Once-Daily vs Twice-Daily Radiotherapy Trial (CONVERT), a multicenter phase 3 trial conducted in patients with limited-stage SCLC from April 7, 2008, to November 29, 2013, patients with TNM stage I to II SCLC were compared with those with stage III disease. Data analysis was performed from November 1, 2017, to February 28, 2018. Interventions: In CONVERT, patients were randomized to receive twice-daily (45 Gy in 30 fractions) or once-daily (66 Gy in 33 fractions) chemoradiotherapy. Prophylactic cranial irradiation (PCI) was offered, if indicated. Main Outcomes and Measures: The primary trial end point was overall survival (OS). TNM staging information was collected prospectively; this was an unplanned analysis because stratification was not performed according to TNM stage. Results: A total of 509 (277 [54.4%] men; mean [SD] age, 61.5 [8.3] years) of 543 patients (93.7%) with TNM staging information were eligible for this subgroup analysis, and 86 of the 509 (16.9%) had TNM stage I to II disease. The median gross tumor volume was smaller in patients with stage I to II disease (38.4 cm 3 ; range, 2.2-593.0 cm 3 ) compared with patients with stage III disease (93 cm 3 ; range, 0.5-513.4 cm 3 ) (P