Lifetime ovulations and epithelial ovarian cancer risk and survival: A systematic review and meta-analysis.
women
lifetime ovulatory years (LOY)
Epithelial ovarian cancer (EOC) risk
2.26 times higher odds of EOC
Abstract
To assess the relationship between lifetime ovulatory years (LOY) and Epithelial ovarian cancer (EOC) risk and survival. A systematic review was performed in accordance with PRISMA guidelines. Relevant studies were identified from PubMed, MEDLINE, and Embase through December 31, 2021 combining the following search: [("ovulation" or "ovulation cycles" or "ovulatory age" or "ovulatory cycles") and ("ovarian cancer" or "ovarian neoplasms") and ("humans" and "female")]. Reference lists of identified articles were searched for additional studies. Studies were excluded from consideration if they were not a published, peer-review article; not in English; lacked data on effect sizes; had data included in another publication; or were a review article, cross-sectional study, or case report. Two independent investigators screened abstracts and full texts for eligibility, extracted study-level data, and assigned study quality. Disagreements between abstractors were discussed and resolved by consensus. Thirty-one reports were included in the qualitative review of LOY and EOC risk, inclusive of 24 studies with sufficient data to be included in the meta-analysis. Women with the highest level of LOY had 2.26 times higher odds of EOC than women with the lowest level of LOY (95% CI 1.94-2.83). LOY was associated with risk of serous (pooled OR 2.31, 95% CI 1.60-3.33) and endometrioid tumors (pooled OR 3.05, 95% CI 2.08-4.45) but not mucinous disease (pooled OR 1.52, 95% CI 0.87-2.64). There were only four studies examining the LOY-survival association, which precluded a quantitative assessment; however, three of the published studies reported worse outcome with greater LOY. LOY is a risk factor for specific EOC histotypes and may also influences EOC survival. Standard definitions of LOY, participant-level data, and larger sample size will enable more precise quantitation of the LOY-EOC association, which can inform EOC risk assessment models.