Adverse Events in Patients With Esophageal Cancer Treated With Nivolumab in Combination With Radiotherapy

BACKGROUND/AIM: When nivolumab is administered as second-line therapy for esophageal cancer, radiotherapy may also be provided in cases either concurrently or sequentially. The aim of this study was to retrospectively examine whether the incidence of adverse events increases in such cases. PATIENTS AND METHODS: Twenty-two esophageal cancer patients [17 males and 5 females; mean age 71 years (range=58-87 years)] treated with nivolumab were included. Patients were divided into two treatment groups: nivolumab alone (N group) (12 patients) and nivolumab combined with radiotherapy (R group) (10 patients). All patients had squamous cell carcinoma. The primary outcomes measured were the severity and frequency of adverse events. RESULTS: Adverse events were seen in 6 of the 12 patients in the N group and 8 of the 10 in the R group. There were significantly more adverse events in the R group (p=0.035), but no difference in Grade 3 or higher adverse events (p=0.781), indicating that the adverse events were controllable. There was no significant difference in treatment effect between the N and R groups. CONCLUSION: In this report, 50% of adverse events in the N group were grade 3-4, 25% of which were grade 4, as seen in previous reports. In the present study, the side effects were not enhanced by treatment with immune checkpoint inhibitors plus radiotherapy. Immune checkpoint inhibitors plus radiation therapy would be a relatively safe treatment and may become an option for esophageal cancer treatment in the future.