The Association Between Hysterectomy and Ovarian Cancer Risk: A Population-Based Record-Linkage Study

Abstract

Background: Recent studies have called into question the long-held belief that hysterectomy without oophorectomy protects against ovarian cancer. This population-based longitudinal record-linkage study aimed to explore this relationship, overall and by age at hysterectomy, time period, surgery type, and indication for hysterectomy.

Methods: We followed the female adult Western Australian population (837 942 women) across a 27-year period using linked electoral, hospital, births, deaths, and cancer records. Surgery dates were determined from hospital records, and ovarian cancer diagnoses (n = 1640) were ascertained from cancer registry records. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between hysterectomy and ovarian cancer incidence.

Results: Hysterectomy without oophorectomy (n = 78 594) was not associated with risk of invasive ovarian cancer overall (HR = 0.98, 95% CI = 0.85 to 1.11) or with the most common serous subtype (HR = 1.05, 95% CI = 0.89 to 1.23). Estimates did not vary statistically significantly by age at procedure, time period, or surgical approach. However, among women with endometriosis (5.8%) or with fibroids (5.7%), hysterectomy was associated with substantially decreased ovarian cancer risk overall (HR = 0.17, 95% CI = 0.12 to 0.24, and HR = 0.27, 95% CI = 0.20 to 0.36, respectively) and across all subtypes.

Conclusions: Our results suggest that for most women, having a hysterectomy with ovarian conservation is not likely to substantially alter their risk of developing ovarian cancer. However, our results, if confirmed, suggest that ovarian cancer risk reduction could be considered as a possible benefit of hysterectomy when making decisions about surgical management of endometriosis or fibroids.

Figure 1.

Association between hysterectomy for a benign indication and invasive epithelial ovarian cancer, by (A) period of hysterectomy and (B) age at hysterectomy, compared to no hysterectomy. Time was censored at hysterectomy for malignancy. Hysterectomy is time-varying. Ovarian cancer includes primary ovarian, fallopian tube, and peritoneal cancer. Models were stratified by decade of birth and adjusted for age at study entry, tubal ligation (yes/no), and parity (3 or more vs 0–2 births). In (B), patterns were similar if we assigned birthdate at the electoral birth-year band midpoint.