BackgroundSurgical resection of esophageal cancer is frequently performed to achieve a complete cure. However, the postoperative recurrence rate is 36.8–42.5%, leading to poor prognosis. Radiation therapy has been used to treat recurrences; solitary recurrence has been proposed as a prognostic factor for radiation therapy, though its significance is unclear.18F-fluorodeoxyglucose positron emission tomography is a highly accurate diagnostic modality for esophageal cancer. This retrospective study aimed to analyze the outcomes of solitary postoperative recurrences of esophageal squamous cell carcinoma diagnosed with18F-fluorodeoxyglucose positron emission tomography and treated with definitive radiation therapy.MethodsWe examined 27 patients who underwent definitive radiation therapy for single or multiple postoperative recurrences of esophageal squamous cell carcinoma between May 2015 and April 2021.18F-fluorodeoxyglucose positron emission tomography/computed tomography was performed within 3 months before the commencement of radiation therapy. Kaplan–Meier, univariate, and multivariate analyses were performed to examine the overall survival and identify potential prognostic factors.ResultsThe 1-, 2-, and 3-year overall survival rates were 85.2%, 62.6%, and 47.3%, respectively, and solitary recurrence was the only significant factor associated with overall survival (P= 0.003). The 1-, 2-, and 3-year overall survival rates in patients with solitary recurrence were 91.7%, 80.2%, and 80.2%, respectively, and in patients with multiple recurrences they were 80.0%, 50.3%, and 25.1%, respectively. Multivariate analysis also showed solitary recurrence as a significant factor for overall survival.ConclusionsWhen diagnosed with18F-fluorodeoxyglucose positron emission tomography/computed tomography, solitary recurrence appears to have a more favorable prognosis than multiple recurrences.