Background: Recent studies have called into question the long-held belief that hysterectomy without oophorectomy protects against ovarian cancer.
Aim: This population-based longitudinal record-linkage study aimed to explore this relationship, overall and by age, time-period, surgery type, and indication.
Methods: We followed 837,942 women on the Western Australian electoral roll across a 27-year period using linked hospitals, births, deaths, and cancer records. Dates of hysterectomy (n=78,596) and oophorectomy were determined from hospital records and ovarian cancer diagnoses (n=1,655) 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 was not associated with risk of invasive ovarian cancer overall (HR [95% CI] 0.99 [0.87-1.13]), or the most common serous subtype (1.05 [0.90-1.24]). Estimates did not vary significantly by age, time-period or surgical approach. However, among women with endometriosis (6%) or with fibroids (6%), hysterectomy was associated with substantially decreased ovarian cancer risk, overall (HR [95% CI] 0.18 [0.13-0.25] and 0.28 [0.21-0.38], 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, while our findings among women with endometriosis or fibroids require replication, these suggest that reducing ovarian cancer risk could be considered as a possible benefit when making decisions about surgical management of these conditions.