# Prognostic impact of serum interleukin-6 and 17 level in patients with bladder cancer: a systematic review and meta-analysis

## TL;DR

This study finds that high levels of interleukin-17 in the blood are linked to worse survival in bladder cancer patients, while interleukin-6 shows no such link.

## Contribution

The study provides the first meta-analysis on the prognostic value of serum interleukin-6 and -17 in bladder cancer.

## Key findings

- High serum IL-17 levels are significantly associated with worse overall survival in bladder cancer patients.
- Elevated serum IL-6/17 levels are strongly linked to poorer disease-free survival in bladder cancer patients.
- No significant association was found between serum IL-6/17 levels and disease-specific survival.

## Abstract

Interleukin, a noninvasive biomarker, holds huge potential for providing valuable insights into the management of inflammatory conditions and tumor diseases. This systematic review and meta-analysis aimed to evaluate the prognostic role of interleukin in bladder cancer (BCa) patients.

A comprehensive search of six English and Chinese databases (PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure (CNKI), Wanfang, and Chinese Biomedical Literature Service System) was conducted from inception to July 10, 2024. Studies investigating the association between serum interleukin levels and BCa were included. Outcome measures encompassed disease-free survival (DFS), overall survival (OS), and disease-specific survival (DSS). Statistical analyses were performed using RevMan 5.4.1, employing random or fixed-effects models as appropriate. Sensitivity, subgroup, and descriptive analyses were also conducted.

A total of seven studies involving 1,505 patients were included. Four studies reported the association between serum interleukin-6/17 (IL-6/17) and OS in BCa. Patients with elevated serum IL levels exhibited a worse OS (HR = 2.28; 95% CI [1.03–5.05]; P = 0.04); however, subgroup analysis revealed that only high serum IL-17 levels were significantly associated with shorter OS, while IL-6 levels showed no association with OS. Six studies examined the relationship between serum IL-6/17 and DFS in BCa. Patients with elevated serum IL levels were associated with poorer DFS (HR = 2.57; 95% CI [1.55–4.26]; P < 0.001). This association remained consistent across subgroup analyses based on interleukin type, publication country, and surgical methods. Only two studies investigated the relationship between serum IL-6/17 and DSS in BCa, with no significant association found (HR = 1.58; 95% CI [1.00-2.51]; P = 0.05).

This meta-analysis demonstrates a strong association between serum interleukin levels and survival outcomes in BCa, suggesting that serum interleukin testing may be a valuable clinical tool for predicting patient outcomes and guiding treatment decisions.