No association between the risk of breast cancer and systemic lupus erythematosus: evidence from a meta-analysis

Several studies have estimated breast cancer risk in patients with systemic lupus erythematosus (SLE) relative to the general population. However, the results have been inconclusive. Therefore, we conducted a meta-analysis to ascertain a more comprehensive conclusion. A systematic literature search of electronic databases including PubMed, Web of Science, Embase, Cochrane Library, and Scopus was conducted to identify eligible studies using multiple search strategies. Based on the degree of heterogeneity, a random-effect model was chosen to calculate the pooled standardized incidence rate (SIR) with 95% confidence interval (CI), to estimate the strength of association between SLE and breast cancer incidence risk. A total of 18 eligible studies including 110,720 patients with SLE were enrolled in this meta-analysis. The combined results showed no significant association between SLE and breast cancer incidence (SIRs = 1.012 (95% CI, 0.797-1.284)). Subgroup analysis by study type, ethnicity, follow-up years, sample size, and SLE diagnostic criteria also showed no altered risk for breast cancer incidence (the summary risk estimate of each subgroup ranged from 0.82 to 1.40 with no statistical significance). This meta-analysis suggests no direct association between SLE and risk of breast cancer incidence.