Effect of Serum Interleukin-6 Concentration on the Prognosis After Radiotherapy for Patients With Hepatocellular Carcinoma.

Objective: The aim of this study was to explore the association between interleukin-6 (IL-6) concentration before radiotherapy (RT) and the prognosis after RT for patients with hepatocellular carcinoma (HCC). Methods: The clinical data for 101 patients with HCC who received RT from October 2016 to June 2021 were retrospectively analyzed. In these patients, the tumors were confined to the liver, and IL-6 concentration was measured before RT. The survival rate was calculated using the Kaplan-Meier method, and the Cox proportional hazards regression model was used to explore the independent factors affecting the patients' prognosis. X-tile software was used to obtain the optimal cut-off value of pre-RT IL-6 concentration (7.8 pg/mL) for overall survival (OS). Results: The 1-, 2-, and 3-year OS rates were 84.4%, 55.8%, and 34.7%, respectively, for patients with a pre-RT IL-6 concentration > 7.8 pg/mL versus 96.0%, 80.1%, and 80.1%, respectively, for those with a pre-RT IL-6 concentration ≤ 7.8 pg/mL. The OS rates of the two groups were significantly different (p < 0.001). The median progression-free survival (PFS) time was 7.5 months versus 15.1 months for patients with pre-RT IL-6 concentrations > 7.8 pg/mL and ≤ 7.8 pg/mL, respectively (p=0.001). Pre-RT IL-6 concentration was an independent prognostic factor of OS (hazard ratio [HR] = 3.421, 95% confidence interval [CI]: 1.477-7.927, p=0.004). Pre-RT IL-6 concentration (HR = 2.235, 95% CI: 1.176-4.246, p=0.014) and age (HR = 0.615, 95% CI: 0.383-0.987, p=0.044) were independent prognostic factors for PFS. Conclusions: The prognosis of HCC patients receiving RT was worse for those with a pre-RT serum IL-6 concentration > 7.8 pg/mL than those with a pre-RT serum IL-6 concentration ≤ 7.8 pg/mL. Pre-RT IL-6 concentrations may affect the prognosis of HCC patients.