Background: The risk of urologic cancers in patients with systemic lupus erythematosus (SLE) remains uncertain. We investigated the association between SLE and incident urologic cancers through a systematic review and meta-analysis.
Methods: We searched the PubMed, EMBASE, and the Cochrane Library to identify articles that recorded prostate, bladder, or kidney cancers in SLE patients from inception to August 31, 2018. We included observational, case-control, or cohort studies with no language restriction. Two investigators screened and extracted the data independently.
Results: Fourteen cohort studies with 83,860 SLE patients were finally analyzed. Overall, SLE patients were at increased risk of bladder cancer (hazard ratio [HR], 1.92; 95% confidence interval [CI], 1.15–3.21) but not of prostate or kidney cancer. However, subgroup analyses showed a reduced risk of prostate cancer in <10-year follow-up studies (HR, 0.68; 95% CI, 0.51–0.89) and an elevated risk of kidney cancer in patients with SLE in Western studies (HR, 2.00; 95% CI, 1.02–3.92), community-based studies (HR, 4.54; 95% CI, 2.17–9.52), prospective studies (HR, 6.84; 95% CI, 2.71–17.26), <10-year follow-up studies (HR, 1.88; 95% CI, 1.38–2.57), and low-quality studies (HR, 2.05; 95% CI, 1.50–2.80).
Conclusion: This study indicates that SLE increases the risk of bladder cancer but not prostate or kidney cancer. Well-designed long-term studies are required to confirm these associations.