Reinholdt K, Kjaer SK, Guleria S, Frederiksen K, Mellemkjær L, Munk C, Jensen A. Risk of endometrial cancer among women with benign ovarian tumors - A Danish nationwide cohort study.
Gynecol Oncol 2020;
157:549-554. [PMID:
32139149 DOI:
10.1016/j.ygyno.2020.02.032]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/23/2020] [Accepted: 02/24/2020] [Indexed: 01/10/2023]
Abstract
OBJECTIVE
The few studies on the association between benign ovarian tumors and endometrial cancer have been inconclusive. Using data from a large Danish register-based cohort study, we assessed the overall and type-specific risk of endometrial cancer among women with a benign ovarian tumor.
METHODS
We identified all Danish women diagnosed with a benign ovarian tumor during 1978-2016 in the Danish National Patient Register (n = 149,807). The study population was followed for subsequent development of endometrial cancer by linkage to the Danish Cancer Register and standardized incidence ratios (SIRs) with corresponding 95% confidence intervals (CIs) were calculated after correction for hysterectomy.
RESULTS
After a one-year delayed study entry, women with benign ovarian tumors had a decreased incidence of endometrial cancer (SIR = 0.74, 95% CI: 0.68-0.81) compared with women in the general Danish population. Both solid benign ovarian tumors (SIR = 0.79, 95% CI 0.70-0.88) and cystic benign ovarian tumors (SIR = 0.68, 95% CI 0.58-0.78) were associated with decreased incidences of endometrial cancer. Likewise, women with benign ovarian tumors had decreased incidences of both type I and type II endometrial cancer. The incidence of endometrial cancer was decreased to virtually the same magnitude irrespective of the age at diagnosis of a benign ovarian tumor and the reduction persisted throughout the follow-up period.
CONCLUSIONS
The risk of endometrial cancer was decreased beyond the first year after a benign ovarian tumor and the decrease persisted for 20 or more years. The possible underlying mechanisms are not known and should be investigated further.
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