Risk of breast cancer among patients with psoriasis: a systematic review and meta-analysis

Relevant evidence regarding the risk of incident breast cancer in patients with psoriasis is lacking. Hence, this systematic review and meta-analysis aimed to assess the risk of breast cancer in patients with psoriasis. We searched the PubMed, Cochrane Library, and Embase databases from inception to December 31, 2021, for relevant cohort studies without language limitations. The Newcastle-Ottawa Scale was used to determine the quality of the selected papers. A random-effects model meta-analysis was performed to obtain the pooled hazard ratio (HR) with a 95% confidence interval (CI) for breast cancer in relation to psoriasis. We also performed a subgroup analysis of patients with mild-to-moderate-to-severe psoriasis. We included seven cohort studies, all of which were considered high quality, and three of them provided data for meta-analysis. The risk for breast cancer did not increase among patients with psoriasis (pooled HR: 1.11, 95% CI 0.97-1.27; I-2 = 67%). In the subgroup analysis, the risk for breast cancer did not significantly increase among patients with mild psoriasis (pooled HR: 1.04, 95% CI 0.97-1.12; I-2 = 6%), and the risk for breast cancer did not significantly increase among those with moderate-to-severe psoriasis (pooled HR: 0.96, 95% CI 0.72-1.28; I-2 = 0%). Patients with mild or moderate-to-severe psoriasis are not at an elevated risk of breast cancer.