Bidirectional association between breast cancer and meningioma: a systematic review and meta-analysis.

Background: An association between breast cancer and meningioma has been suggested in cohort studies. We aimed to perform a systematic review and meta-analysis to determine whether there is an association between initial breast cancer and subsequent meningioma diagnosis and vice versa.

Methods: A systematic literature search was performed on Medline, Embase, Scopus and Google scholar from inception up to April 2023. A meta-analysis of selected studies was performed using Review Manager 5.4.

Results: There were eight studies included in the systematic review. Seven had reported Standardized Incidence Ratio (SIR) for female patients and were suitable for the meta-analysis. Only one study reported SIR for male patients. For the association between initial breast cancer and subsequent meningioma, in 795 000 female patients with follow-up ranging from 7 to 13 years, the SIR was 1.27 (95% CI: 1.20-1.34, P-value <0.00001). For the association between initial meningioma and subsequent breast cancer, in 28 000 female patients with follow-up ranging from 6 to 15 years, the SIR was 1.32 (95% CI: 1.21-1.45, P-value <0.00001). There were low heterogeneity and no significant publication bias.

Conclusion: There was a small but significant association between initial breast cancer and subsequent meningioma as well as initial meningioma and subsequent breast cancer in female patients. The potential underlying mechanisms and risk factors were unclear from current literature and would be a potential area for future research.