The incidence of breast cancer in RA patients remains controversial. Thus we performed a meta-analysis to investigate the impact of RA on breast cancer.
Published literature was available from PubMed, Embase, and Cochrane Library. Pooled standardized incidence rate (SIR) was computed by random-effect model analysis.
We identified 16 separate studies in the present study, in which the number of patients ranged from 458 to 84,475. We did not find the increased cancer risk in RA patients (SIR=0.86, 95% CI=0.72-1.02). However, subgroup analysis showed that breast cancer risk in RA patients was positively different in Caucasians (SIR=0.82, 95% CI=0.73-0.93) and non-Caucasians (SIR=1.21, 95% CI=1.19-1.23), respectively. In subgroup analysis by style, a reduced incidence was found in hospital-based case subjects (SIR=0.82, 95% CI=0.69-0.97). Similarly, subgroup analysis for adjusted factors indicated that in A3 (age and sex) and A4 (age, sex, and race/ethnicity) the risk was decreased (SIR=0.87, 95% CI=0.76-0.99; SIR=0.63, 95% CI=0.59-0.67).
The meta-analysis revealed no increased breast cancer risk in RA patients. However, in the subgroup analysis, the risk of breast cancer is increased in non-Caucasians patients with RA while it decreased in Caucasian population, hospital-based case subjects, and A3 group. Such relationship may provide preference for risk of breast cancer in different population.