The association between preoperative serum interleukin-6 levels and postoperative prognosis in patients with T2 gallbladder cancer.

Background: Interleukin-6 (IL-6) is closely associated with tumor progression. Whether it can predict postoperative prognosis of patients with T2 gallbladder cancer (GBC) remains controversial.

Methods: We retrospectively collected the medical records of 125 patients with T2 GBC. Then, we analyzed the association between preoperative serum IL-6 levels and postoperative survival by multivariate Cox analyses and Kaplan-Meier curves in exploratory subgroups.

Results: Predictive effects of serum IL-6 levels on overall survival were similar across most of the evaluated subgroups, except in different tumor location subgroups. The independent odds ratio (OR) of serum IL-6 levels was 2.57 (95%CI 1.73-3.82) in the hepatic side subgroup, while it was 1.15 (95%CI 0.68-1.93) in the peritoneal side subgroup (P = 0.014 for interaction). When we categorized serum IL-6 levels by median value (4.2 pg/mL), the 5-year survival rate of patients with high serum IL-6 levels was significantly higher in the hepatic side subgroup (58.5% vs 14.8%, P < 0.001), but no such difference was found in the peritoneal side subgroup (62.2% vs 67.6%, P = 0.722).

Conclusions: Preoperative serum IL-6 is significantly associated with prognostic implications in patients with hepatic side T2 GBC, not in those with peritoneal side tumors.