Clinical outcomes after intensity-modulated proton therapy with concurrent chemotherapy for inoperable non-small cell lung cancer

Background & purpose: We report disease control, survival, and toxicity in patients with advanced inoperable non-small cell lung cancer (NSCLC) receiving concurrent chemotherapy and intensity-modulated proton therapy (IMPT) at a single institution. Material and methods: All patients were treated with IMPT with concurrent chemotherapy. Endpoints assessed were local, regional, and distant control, disease-free survival (DFS), and overall survival (OS). Results: Fifty-one patients were enrolled with a median follow-up time of 23.0 months; 39 (76%) were treated with a simultaneous integrated boost to the gross tumor volume (GTV). The median GTV dose was 67.3 CGE and the median CTV dose was 60.0 CGE. Median OS and DFS times were 33.9 months and 12.6 months. The 3-year local control rate was 78.3%. Treatment was well tolerated, with a grade 3 toxicity rate of 18% (9 events: 4 esophagitis, 3 dermatitis, 1 esophageal stricture, and 1 fatigue) and no grade 4 or 5 toxicity. The most common grade 2 toxic effects were esophagitis (22 [43%]), dermatitis (16 [31%]), pain (15 [29%]), and fatigue (14 [27%]). Conclusions: Treatment of inoperable NSCLC with IMPT and concurrent chemotherapy achieves excellent disease control with tolerable toxicity.