Outcomes and toxicity following high-dose radiation therapy in 15 fractions for non-small cell lung cancer

Purpose Accelerated hypofractionated radiation therapy (AHRT) is increasingly used for select lung cancer patients. We evaluated clinical outcomes and predictors of pulmonary/esophageal toxicity in patients treated with ≥52.5 Gy in 15 fractions. Methods and materials We evaluated 229 patients treated with radiation therapy doses ≥52.5 Gy in 15 fractions for non-small cell lung cancer from January 2009 through January 2016. Toxicity was scored using Common Terminology Criteria for Adverse Events, v4.0. Univariate and multivariate logistic regression was used to identify predictors of toxicity. Overall survival, progression-free survival, and local control were estimated using the Kaplan-Meier method. Predictors of clinical outcome were modeled using Cox proportional hazards regression. Results Median follow-up was 7 months. Forty-two patients (19%) developed grade ≥2 pneumonitis, and 9 (4%) developed grade ≥3 esophagitis. In multivariate analysis, age >75 years (odds ratio [OR], 2.56; 95% confidence interval [CI], 1.24-5.25; P = .01) and percentage of lung volume receiving doses of >10 Gy higher than 32% were associated with grade ≥2 pneumonitis (OR, 2.79; 95% CI, 1.39-5.79; P = .005). On univariate analysis, esophagus mean dose ≥17 Gy (OR, 10.14; 95% CI, 1.82-189.8; P = .006), gross tumor volume size ≥71 cm³ (P = .002), and planning target volume size ≥409 cm³ (P = .02) were associated with development of grade ≥3 esophagitis. In patients with stage II/III disease (n = 73), median local control was not reached, median overall survival was 14 months, and median progression-free survival was 6 months. Conclusions AHRT in 15 fractions can be safe and effective. Consideration for using AHRT with immunotherapy and sequential chemotherapy for improved out-of-radiation field and distant control is warranted.