Long-term outcomes of high-dose hyperfractionated thoracic radiotherapy for limited-stage small-cell lung cancer

Concurrent chemoradiotherapy with thoracic radiotherapy of 45 Gy in 30 twice-daily fractions is the standard treatment for limited-stage small-cell lung cancer (LS-SCLC). However, the optimal thoracic radiotherapy dose remains uncertain. This study aimed to evaluate the efficacy and safety of high-dose hyperfractionated radiotherapy for LS-SCLC. We retrospectively analyzed 38 patients with LS-SCLC who received high-dose hyperfractionated radiotherapy at multiple institutions in Yamagata Prefecture between 2008 and 2012. Radiotherapy was delivered at a total dose of 60 Gy in 50 twice-daily fractions of 1.2 Gy. The median follow-up was 31 months for the entire cohort and 107 months for surviving patients. The 3- and 5-year overall survival and progression-free survival were 46.1 and 26.2%, and 36.9 and 26.9%, respectively. The cumulative incidence of local recurrence in the high-dose region at 3- and 5-years was 13.5 and 18.9%, respectively. Grade 3 radiation pneumonitis occurred in three patients (7.9%). No grade 4 or higher radiation pneumonitis or grade 3 or higher esophagitis was observed. Grade 4 cytopenia occurred in six patients (16%). High-dose hyperfractionated radiotherapy may be a feasible dose-escalated option for patients with LS-SCLC, with acceptable toxicity. Published data on the long-term outcomes of this specific regimen are limited.