Outcomes following hypofractionated radiation therapy alone for surgically unfit early esophageal squamous cell carcinoma patients; a retrospective single center analysis

Background and purpose: To report the feasibility of hypofractionated radiation therapy (RT) alone for early stage esophageal squamous cell carcinoma (ESCC) patients.Materials and methods: The oncologic outcomes of 60 cT1-2 N0 ESCC patients who received hypofractionated RT (54 similar to 60 Gy by 3.0 Gy per fraction) from 2004 to 2018 were retrospectively evaluated.Results: The 5-year rates of local control (LC), progression-free survival, cancer-specific survival, and overall survival were 81.1 %, 44.2 %, 73.7 %, and 54.5 %, respectively. In Cox regression analysis, tumor length < 3 cm was correlated with favorable LC (HR 0.167, p = 0.090), and the 5-year LC rates were 95.7 % and 72.0 % in < 3 cm and >= 3 cm subgroups, respectively (p = 0.053). Grade >= 2 esophagitis was observed in 44 patients (73.3 %) and grade >= 2 esophageal strictures developed in five (8.3 %), respectively. The patients with >= 3 cm tumor more frequently suffered from grade >= 2 esophagitis (13/24 vs. 31/36, p = 0.006) and grade >= 2 esophageal stricture (0/24 vs. 5/36, p = 0.056), respectively. The patients with cT2 tumor suffered from grade >= 2 esophagitis more frequently than those with T1 tumor (29/44 vs. 15/16, p = 0.03).Conclusions: Hypofractionated RT alone, with the merit of short treatment course, could be used as feasible option in treating the early stage ESCC patients who are unfit for surgical resection or chemoradiation. Especially, tumor length < 3 cm seems a good indication of this treatment scheme based on favorable LC rate with low incidence of esophageal toxicities.