Does inflammatory bowel disease increase the risk of lower urinary tract tumors: a meta-analysis

Background: Inflammatory bowel disease, including ulcerative colitis and Crohn's disease, is characterized by chronic inflammation that could be a risk factor for extraintestinal cancer. The aim of this study is to evaluate whether inflammatory bowel disease is related to the risk of lower urinary tract tumors. Methods: A systematical research was performed on various medical databases including PubMed, the Cochrane Library, Embase and Web of Science from inception to April 2020. Data were independently extracted by two reviewers. The Newcastle-Ottawa Scale and the Oxford Centre for Evidence-Based Medicine criteria were used to assess the quality of included articles. The analysis was completed by STATA version 14.2. Results: Six hundred and twelve of records were initially identified and 16 studies were included in the final analysis. In general, inflammatory bowel disease patients were not at increased risk of prostate cancer, bladder cancer and male genital cancer. In the subgroup analysis, Crohn's disease patients seemed to have borderline increased risk of prostate cancer [standardized incidence ratio: 1.05; 95% confidence interval (CI): 0.90-1.21; 1 2 =15.1%] and bladder cancer (standardized incidence ratio: 1.19; 95% CI: 0.94-1.44; I-2 =0.0%), and ulcerative colitis patients seemed to have borderline increased risk of prostate cancer (standardized incidence ratio: 1.13; 95% CI: 0.93-1.33; I-2 =73.5%). Conclusions: Inflammatory bowel disease did not significantly increase the risk of prostate cancer, bladder cancer and male genital cancer. Crohn's disease patients seemed to have a higher risk of prostate cancer and bladder cancer, and ulcerative colitis patients seemed to have a higher risk of prostate cancer. ulcerative colitis patients in East Asian countries have significantly increased prostate cancer risk.