Outcomes of radiotherapy combined with immune checkpoint inhibitors in locally advanced unresectable esophageal squamous cell carcinoma: a retrospective analysis.

Background: The benefit of immune checkpoint inhibitors (ICIs) for esophageal cancer has been investigated and integrated into the treatment strategy. The integration of ICIs with radiotherapy offers significant potential for future applications in patients with locally advanced unresectable esophageal squamous cell carcinoma (ESCC). This study aimed to investigate the outcomes of ICIs combined with radiotherapy.

Methods: In this study, we enrolled patients with locally advanced unresectable ESCC who presented to Zhejiang Cancer Hospital between May 2019 and August 2021. The characteristics, survival outcomes, and toxicities of the patients were analyzed. Univariable and multivariable Cox regression analyses were performed to identify the factors associated with survival.

Results: A total of 92 patients with locally advanced unresectable ESCC were enrolled. The median follow-up period was 18.2 months. The rates of 24-month progression-free survival (PFS) and overall survival (OS) in the entire group were 33.7% and 39.1%, respectively. Radiotherapy showed better survival outcomes when concurrently administered with ICIs or chemotherapy than when used as a standalone treatment. High-grade (≥ grade 3) adverse events occurred in 48.9% of our patients. One patient died of severe pneumonia after receiving the combination therapy; this patient had a previous history of severe interstitial pneumonia.

Conclusions: Radiotherapy combined with ICIs is a promising method to treat patients with locally advanced unresectable ESCC. Future prospective randomized clinical trials should evaluate combination strategies for such patients.