Subtypes of Benign Breast Disease as a Risk Factor of Breast Cancer: A Systematic Review and Meta Analyses

Background: Researchers suggest that benign breast disease (BBD) is a key risk factor for breast cancer. The present study aimed to determinate the risk level of breast cancer in terms of various BBD subgroups. Methods: A meta-analysis was performed to determinate the risk of breast cancer associated with BBD. Observational studies (traditional case-control studies, nested case-control studies, and cohort studies) published from January 2000 to June 2015 were assessed to evaluate the risk of developing breast cancer related to BBD. Various databases such as Medline (PubMed), Web of Science (ISI), Scopus, and Google Scholar were searched. The additional search included the Journal of Breast Cancer Research and Treatment and the Journal of Cancer Research. Results: Twenty studies out of 21 were used to estimate the risk of developing breast cancer related to proliferative disease without atypia versus non-proliferative disease and the reported risk ranged from 1.04 to 1.83. The reported risk of developing breast cancer related to proliferative disease with atypia versus non-proliferative disease in 21 studies ranged from 1.59 to 4.74. Based on 20 studies, the pooled risk estimates for developing breast cancer related to proliferative disease without atypia versus non-proliferative disease was 1.58 (95% CI: 1.51-1.66). Based on 21 studies, the pooled risk estimates for developing breast cancer related to proliferative disease with atypia versus non-proliferative disease was 3.49 (95% CI: 3.23-3.77). Conclusion: The overall result of this review showed an elevated risk for breast cancer related to BBD subtypes. We propose better strategies for screening recommendations for such women.