Long-Term Clinical Outcomes and Safety Analysis of Superficial Esophageal Cancer Patients Treated with Definitive or Adjuvant Radiotherapy

(1) Background: The role of radiotherapy (RT) in superficial esophageal squamous cell cancer (ESCC) remains unclear. The objective of our study was to perform a detailed outcome and safety analysis of RT as a definitive or adjuvant treatment for T1N0M0 staged ESCC patients. (2) Methods: A total of 55 patients treated with endoscopic resection (ER) + RT/concurrent chemoradiotherapy (CCRT) or RT/CCRT from January 2011 to June 2021 were included in this study. Eighteen patients with risk factors received ER + RT/CCRT, and thirty-seven patients solely received RT/CCRT. Kaplan-Meier curves were used to calculate the clinical outcomes, and toxicities were scored. (3) Results: The median follow-up time was 51.9 months. The estimated 5-year local recurrence-free survival (LRFS) and overall survival (OS) were 88.9% and 94.4% in the ER + RT/CCRT group and 91.8% and 91.7% in the RT/CCRT group. The predominant failure pattern was in-field local failure (5.5%, 3/55), with one patient in the ER + RT/CCRT group and two patients in the RT/CCRT group. One patient (1.8%, 1/55) had lung metastasis in the RT/CCRT group. The most common toxicities were Grades 1-2 in all patients, including esophagitis (74.5%, 41/55), myelosuppression (49.1%, 27/55) and esophageal stricture after RT (27.3%, 15/55). Two patients (11.1%, 2/18) and four patients (10.8%, 4/37) had Grade 3 esophageal stricture after RT in the ER + RT/CCRT group and RT/CCRT group, respectively. No patients experienced a Grade 4 or higher toxicity, and there were no treatment-related deaths. (4) Conclusions: Definitive or adjuvant RT/CCRT is an effective treatment alternative for superficial ESCC patients with satisfactory clinical outcomes and acceptable toxicities.