Optimized radiotherapy to improve clinical outcomes for locally advanced lung cancer.

Background: We aimed to evaluate the toxicity, loco-regional control (LRC) and overall survival (OS) associated with accelerated intensity-modulated radiotherapy (IMRT) for locally advanced lung cancer.
Methods: Seventy-three patients were consecutively treated with IMRT from November 2011 to August 2016. A total dose of 66 Gy was delivered using two different schedules of radiotherapy: simultaneous modulated accelerated radiotherapy (SMART) (30 × 2.2 Gy, across 6 weeks) with or without chemotherapy, or moderate hypofractionated radiotherapy (HRT) (24 × 2.75 Gy, across 4 weeks) in patients unfit to receive concomitant chemotherapy. Data on esophageal and pulmonary toxicities, LRC and OS were prospectively collected.
Results: The median follow-up duration was 44 months. Severe pneumonitis and esophagitis (grade 3-4) were observed in 7% and 1% of patients respectively, with only one case of grade 4 (pneumonitis). Overall, the 1-year and 2-year LRCs were 76% [95 confidence interval (CI)%: 66-87%] and 62% [95 CI%: 49-77%] respectively. The 1 and 2-year OS rates were 72% [95% CI: 63-83%] and 54% [95 CI%: 43-68%] respectively. None parameters were correlated with LRC or OS. In particular, no difference was observed between patients treated with SMART and H-RT (p = 0.26 and 0.6 respectively), with a 1-year LRC of 74% [95 CI%: 62-86%] for SMART and 91% [95 CI%: 74-100%] for H-RT. No significant differences were observed in the toxicity rates associated with each of the RT schedules.
Conclusions: Accelerated IMRT for locally advanced lung cancer is associated with low toxicities and high LRC. Moderate hypofractionated RT, by decreasing the total treatment time, may be promising in improving clinical outcomes.