Association of interleukin-6 serum levels with local tumor stage and lymph node metastasis of urothelial carcinoma.

Introduction: Elevated preoperative interleukin-6 (IL-6) blood levels in urothelial carcinoma (UC) patients undergoing radical cystectomy (RC) have been linked to adverse pathological features. The aim of this prospective study of patients undergoing RC was to analyze whether preoperative IL-6 serum levels (i) correlate with local tumor stage, (ii) are associated with lymph node metastasis, and (iii) are elevated in patients with other oncologic or nononcologic indications for RC.

Materials and methods: Patients undergoing RC for oncologic or nononcologic indications were prospectively included. IL-6 serum levels were measured preoperatively. Statistical analysis included Spearman correlation analysis and Receiver Operating Characteristics (ROC) analysis.

Clinicaltrials: gov: NCT05153694.

Results: Between December 2021 and November 2024, 214 patients underwent RC at our department. Preoperative IL-6 serum levels were measured in 169 patients who provided informed consent. In UC patients, IL-6 levels correlated with local tumor stage (r = 0.30, P = 0.001) and higher levels were associated with lymph node metastasis (P = 0.001). The AUC was 0.678 (95% CI 0.58-0.77) and 0.681 (95% CI 0.58-0.79) for non-organ confined tumor growth and lymph node metastasis, respectively. No significant difference in preoperative IL-6 serum levels was observed between UC patients and patients with other oncologic or nononcologic indications for RC.

Conclusion: This prospective study found that elevated preoperative IL-6 serum levels correlated with local tumor stage and were associated with lymph node metastasis in UC patients undergoing RC. However, IL-6 levels were also elevated in patients with other oncologic or nononcologic indications for RC, underscoring the need for careful interpretation of this marker.