High pre-treatment serum interleukin-10 levels are associated with significantly worse overall survival in patients with esophageal squamous cell carcinoma treated with chemoradiotherapy.

• 1-year overall survival rates were 85% in low IL-10 patients versus 56% in high IL-10 patients; 3-year rates were 50% versus 33%.
• Both advanced cancer stage and high IL-10 levels independently predicted shorter survival.

Surgeons might consider serum IL-10 level testing for better risk stratification and to inform potential immunomodulatory treatment decisions.