We aimed to explore the efficacy and toxicity of split-course hypofractionated radiation therapy with concurrent chemotherapy (HRT-CHT) in patients with locally advanced non-small cell lung cancer (LANSCLC) in this single-arm, phase II study.

Patients with LANSCLC were considered eligible if their forced expiratory volume in 1 second/forced vital capacity (FEV/FVC%) and carbon monoxide diffusing capacity (DLCO%) were ≥40% and ≥45%, respectively. HRT-CHT using the intensity modulated radiation therapy technique was administered with 51 Gy in 17 fractions as the first course followed by a break. Patients without disease progression or persistent ≥grade 2 toxicities had an HRT-CHT of 15 to 18 Gy in 5 to 6 fractions as a boost. The primary endpoint was progression-free survival, and the secondary endpoint was overall survival (OS).

Eighty-nine patients were enrolled and analyzed. The median follow-up was 29.5 months for all patients and 35.3 months for the survivors. The objective response rate was 97.8%; the median progression-free survival and OS were 11.0 and 27.0 months, respectively. Grade 3 acute esophagitis/pneumonitis occurred in 15 (16.9%)/7 (7.9%) patients. Grade 3/5 late pneumonitis occurred in 2 (2.2%)/1 (1.1%) patients. Of the 78 (87.6%) who completed the split-course HRT-CHT per protocol, patients with better FEV/FVC% and DLCO% after the break had significantly better OS (for the FEV/FVC1% ≥ 80% vs 60%-79% vs 41%-59% groups, 2-year OS values were 57.2% vs 56.9% vs 0%, respectively, P = .024; for the DLCO% ≥ 80% vs 60%-79% vs 45%-59% groups, 2-year OS values were 70.4% vs 48.4% vs 37.5%, respectively, P = .049).

Split-course HRT-CHT achieved a promising response rate and survival with tolerable toxicity in LANSCLC. Pulmonary function tests are necessary indicators for radiation treatment planning and dose escalation.