Intensity-modulated radiotherapy with more than 60 Gy improved the survival of inoperable patients with locally advanced esophageal squamous cell carcinoma: a population-based real-world study

Abstract Background Intensity-modulated radiotherapy (IMRT) is widely applied during the treatment of esophageal squamous cell carcinoma (ESCC), but the optimal radiation dose still lacks a consensus. The aim of this study was to explore the optimal radiation dose for inoperable locally advanced ESCC patients treated with IMRT in a real-world clinical setting. Methods A total of 90 inoperable ESCC patients with locally advanced stages of Ⅱ-IVA treated with IMRT in our institute between February 1, 2014 and June 30, 2019 were included in this retrospective study. Sixty patients had received > 60 Gy (high dose group) and 30 patients had received ≤ 60 Gy (low dose group). The median radiation dose was 66 Gy (range: 61–70 Gy) and 50.2 Gy (range: 40–60 Gy), respectively. Concurrent chemotherapies were platinum-based regimens. Results The median progression free survival (PFS) and overall survival (OS) of all patients were 7.6 and 14.1 months, respectively. Patients in the high dose group exhibited a significantly better PFS (1-year PFS 34.6% vs 22.8%; 2-year PFS 11.9% vs 0%, P = 0.008) and OS (1-year OS 57.5% vs 39.5%; 2-year OS 31.4% vs 15.8%, P = 0.007). The median PFS in the high and low dose groups were 8.1 and 6.1 months, and the median OS were 15.4 and 8.5 months, respectively. Multivariate Cox analysis showed that radiation dose (> 60 Gy vs ≤ 60 Gy) was independently prognostic factor for OS (HR: 0.44; 95% CI: 0.22–0.89; P = 0.021), but not for PFS (HR: 0.56; 95% CI: 0.31–1.02; P = 0.058). There was no significant difference in treatment-related toxicities of grade ≥ 3 between the 2 groups (P = 0.402). Conclusion This retrospective study confirmed that higher radiation dose (> 60 Gy) resulted in better survival outcomes for inoperable patients with locally advanced ESCC treated with IMRT.