Randomized, Multicenter, Phase 3 Study of Accelerated Fraction Radiation Therapy With Concomitant Boost to the Gross Tumor Volume Compared With Conventional Fractionation in Concurrent Chemoradiation in Patients With Unresectable Stage III Non-Small Cell Lung Cancer: The Korean Radiation Oncology Group 09-03 Trial.

Purpose: We designed the Korean Radiation Oncology Group 09-03 phase III clinical trial to compare accelerated hypofractionated radiation therapy (RT) using a concomitant boost to the gross tumor volume (GTV) with conventionally fractionated 60-Gy RT in patients with stage III unresectable non-small cell lung cancer (NSCLC).

Methods And Materials: A conventionally fractionated RT group (arm 1; 124 patients) received a 2-Gy daily dose to a total cumulative dose of 44 Gy to the planning target volume (PTV) in 22 fractions and 60 Gy to the GTV in 30 fractions over 6 weeks. A hypofractionated RT group (arm 2; 142 patients) received a 1.8-Gy daily dose to the PTV with a synchronous boost of 0.6 Gy to the GTV, for total cumulative doses of 45 Gy to the PTV and 60 Gy to the GTV in 25 fractions over 5 weeks. All patients received concurrent weekly chemotherapy consisting of paclitaxel and cisplatin.

Results: The objective response rate of all patients was 86.5% (arm 1, 84.6%; arm 2, 88.1%; P = .612). The median overall survival was 26 months (arm 1, 26 months; arm 2, 27 months; P = .508). The median progression-free survival was 11 months (arm 1, 10 months; arm 2, 13 months; P = .295). The local tumor control rates at 2 and 5 years were 58.3% and 50.7%, respectively (arm 1, 62.4% and 51.0%, respectively; arm 2, 54.0% and 48.6%, respectively; P = .615). There were no significant between-group differences in the cumulative incidence of grade ≥3 radiation pneumonitis (P = .134) or radiation esophagitis (P = .539).

Conclusions: This clinical trial did not confirm the superiority of accelerated 2.4-Gy hypofractionated RT compared with conventional 2-Gy fractionation in patients with unresectable stage III NSCLC undergoing concurrent chemoradiation therapy.