Association between gynecological cancers and female infertility: insights from bidirectional Mendelian randomization analysis.

Purpose: In recent years, research interest in the potential link between female infertility (FI) and gynecological cancer (GC), including ovarian cancer (OC), endometrial cancer (EC), cervical cancer (CC), and breast cancer (BC), has grown, yet findings remain inconclusive. This study aims to explore the causal relationship between FI and GC using bidirectional two-sample Mendelian randomization (MR) analyses, thereby informing future strategies for FI and GC prevention.

Methods: We utilized SNPs identified from genome-wide association studies (GWAS) on FI and GC. The inverse variance weighted (IVW) method served as the primary approach to assess the causal association between FI and GC. Additionally, five other MR methods-Weighted median, Weighted mode, MR-Egger, Simple mode, and Robust-Adjusted Profile Score-were employed to enhance result robustness and credibility.

Results: In the forward MR analysis, our IVW results indicated no significant association between FI and GC (FI-BC: OR = 0.95, 95% CI: 0.83-1.09, P = 0.47, P-FDR = 0.775; FI-OC: OR = 1.01, 95% CI: 0.84-1.24, P = 0.789, P-FDR = 0.896; FI-CC: OR = 0.80, 95% CI: 0.61-1.06, P = 0.118, P-FDR = 0.775; FI-EC: OR = 1.07, 95% CI: 0.88-1.30, P = 0.490, P-FDR = 0.775).In the reverse MR analysis, we found a marginal association between BC and FI. However, after adjusting for multiple testing using the FDR method, no significant causal relationship was found between BC and FI, suggesting a marginal association (OR = 1.054, 95% CI: 1.001-1.108, P = 0.043, P-FDR = 0.331). For other cancers, no significant causal relationships were observed between OC, CC and EC with FI(OC-FI: OR = 1.043, 95% CI: 0.999-1.087, P = 0.051, P-FDR = 0.331;CC-FI: OR = 0.992, 95% CI: 0.956-1.028, P = 0.654, P-FDR = 0.836; EC-FI: OR = 1.006, 95% CI: 0.956-1.055, P = 0.809, P-FDR = 0.885).

Conclusions: Our study found no significant causal relationship between FI and GC. However, a potential marginal association between BC and FI was observed. These findings underscore the need for further research to confirm this association and emphasize the importance of reproductive protection for young breast cancer patients to preserve fertility.