Incidence of endometrioid and clear-cell ovarian cancer in histological proven endometriosis: the ENOCA population-based cohort study

Marjolein Hermens, van Altena AM, Anne M van Altena, Theodoor E Nieboer, Nieboer TE, Benedictus C Schoot, Schoot BC, B.C. Schoot, van Vliet HAAM, Huib A A M van Vliet, Albert G Siebers, Ruud L M Bekkers
American journal of obstetrics and gynecology · 2020 · vol. 223(1) , pp. 107.e1–107.e11 · doi:10.1016/j.ajog.2020.01.041 · PMID:31981507 · W3002081716
article OA: closed CC0 ⤵ 47 in-corpus citations
View on OpenAlex View on PubMed View at publisher
⚙ AI-generated summary by claude@2026-06, 2026-06-09 ⓘ

This population-based cohort study investigated the incidence of endometrioid and clear-cell ovarian cancer among women with histologically proven endometriosis.

One-sentence paraphrase of the abstract; not a substitute for reading it. No clinical advice. How this works

Abstract

BackgroundSeveral studies have suggested that endometriosis is associated with an increased risk of ovarian cancer, especially for the clear-cell and endometrioid subtypes. However, previous studies lack sufficient power or diagnostic certainty.ObjectiveThe objective of the study was to assess the association between histologically proven endometriosis and ovarian cancer in a large population-based cohort study.Study designWe identified 131,450 women with a histological diagnosis of endometriosis between 1990 and 2015 from the Dutch nationwide registry of histopathology and cytopathology (PALGA). For the control cohort 132,654 women with a benign dermal nevus were matched on age and inclusion year with the endometriosis cases. Histological diagnoses of ovarian, fallopian tubes, and peritoneal cancers between January 1990 and July 2017 were retrieved. Incidence rate ratios were estimated for ovarian cancer and its subtypes for the whole follow-up period as well as for women with more than 1 person-year at risk.ResultsWe found a crude incidence rate ratio of 4.79 (95% confidence interval, 4.33-5.31) and an age-adjusted incidence rate ratio of 7.18 (95% confidence interval, 6.17-8.36) for ovarian cancer overall. Endometrioid and clear-cell ovarian cancer had the highest age-adjusted incidence rate ratio of 29.06 (95% confidence interval, 20.66-40.87) and 21.34 (95% confidence interval, 14.01-32.51), respectively. Median age at ovarian cancer diagnosis was 56 years (interquartile range, 49-63) for the endometriosis cohort and 60 years (interquartile range, 53-67) for the nevus cohort, (P < .05). After excluding women with less than 1 person-year at risk following an endometriosis diagnosis, we found a crude incidence rate ratio of 1.04 (95% confidence interval, 0.91-1.19) and an age-adjusted incidence rate ratio of 1.08 (95% confidence interval, 0.87-1.35) for ovarian cancer overall. However, statistically significant age-adjusted incidence rate ratios of 2.29 (95% confidence interval, 1.24-4.20) for clear-cell ovarian cancer and 2.56 (95% confidence interval, 1.47-4.47) for endometrioid ovarian cancer were found.ConclusionA significantly higher incidence of clear-cell and endometrioid ovarian cancer was found in women with histologically proven endometriosis. Additionally, we found an increased incidence of all ovarian cancer subtypes in histologically proven endometriosis; however, in many of these women, endometriosis and ovarian cancer were diagnosed synchronously after the average menopausal age, which may suggest that the risk of ovarian cancer in endometriosis patients remains, even when clinical endometriosis symptoms are no longer present.

My notes (saved in your browser only)

Condition tags

endometriosis

MeSH descriptors

Carcinoma, Endometrioid Carcinoma, Endometrioid Endometriosis Ovarian Neoplasms Ovarian Neoplasms Aged Carcinoma, Endometrioid Cohort Studies Endometriosis Endometriosis Female Humans Incidence Middle Aged Ovarian Neoplasms

Citation neighborhood

Papers in the corpus that this work cites (lower rings, blue) and that cite this one (upper rings, green). Dot size scales with the paper's in-corpus citation count — bigger dot = more influential within the endo/adeno field. Click a dot to open that paper. [ expand to 2 hops ] — adds papers reached through this work's immediate citers/citees. Heavier; up to 60 extra dots.

References (43)

Cited by (47)

Source provenance

europepmc
last seen: 2026-07-28T06:14:09.330459+00:00
openalex
last seen: 2026-06-10T17:14:06.276822+00:00
pubmed
last seen: 2026-05-13T22:22:17.025735+00:00
unpaywall
last seen: 2026-07-28T06:55:22.213180+00:00
License: CC0 · commercial use OK