EPV228/#80 Increased incidence of ovarian cancer in both endometriosis and adenomyosis

• Published in: International journal of gynecological cancer Vol. 31; no. Suppl 4; p. A119
• Main Authors: Hermens, M, Van Altena, A, Bulten, J, Van Vliet, H, Siebers, A, Bekkers, R
• Format: Journal Article
• Language: English
• Published: Oxford BMJ Publishing Group Ltd 01.11.2021; BMJ Publishing Group LTD
• Subjects: E-Posters; Endometriosis; Ovarian cancer
• ISSN: 1048-891X; 1525-1438
• DOI: 10.1136/ijgc-2021-IGCS.299

ObjectivesRecently we conducted a study in which we found an increased association of ovarian cancer in women with endometriosis. Analyses showed that the cohort included both women with endometriosis externa and adenomyosis. Therefore, in the present study we assessed the association between endometriosis and/or adenomyosis and ovarian cancer.MethodsWe identified all women with histological proven endometriosis (51,544 women) and/or adenomyosis (85,015 women) from the Dutch pathology database (1990–2015) and matched them with women with a benign dermal nevus (132,654 women). Histology results for ovarian cancer were retrieved. We estimated crude and age-adjusted incidence rate ratios (IRR) for ovarian cancer.ResultsWe found 1,017 (2.0%), 1,284 (1.5%) and 471 (0.4%) ovarian cancer cases in the endometriosis, adenomyosis and nevus cohort, respectively. The age-adjusted IRRs were 19.75 (95%CI 16.70–23.35) in the endometriosis cohort and 5.93 (95%CI 4.91–7.16) in the adenomyosis cohort (table 1). The highest IRRs were found for endometrioid and clear cell ovarian cancer subtypes (table 1). Excluding the first year of follow-up did not result in a significant IRR for ovarian cancer overall but resulted in a statistically significant IRRs for clear cell and endometrioid ovarian cancer (table 1).Abstract EPV228/#80 Table 1Observed number of ovarian cancers, estimated incidence rate per 100,000 person-years, crude incidence rate ratios and age-adjusted incidence. Rate ratios of ovarian cancers of women with endometriosis or adenomyosis compared with a benign dermal nevus, per ovarian cancer subtype and overallConclusionsWe found an increased ovarian cancer incidence in both histological proven endometriosis and adenomyosis. This increased incidence was largest for endometriosis. Excluding the first year of follow-up resulted in an increased incidence for endometrioid ovarian cancer in both cohorts and clear cell ovarian cancer in the endometriosis cohort.