Short summary

Ovarian cancer (OC) is the deadliest of all gynecological cancers and a diagnosis in early stages is crucial for the prognosis. Endometriosis is associated with an increased risk of OC. The purpose of this project is to examine whether a small subgroup of women with endometriosis who develop OC, can be identified through a risk profile. This will allow us to identify a subpopulation of women with endometriosis in high risk of OC. These women can then be offered screening or profylactic surgery.

Rationale

BACKGROUND:

Endometriosis (E) is associated with an increased risk of ovarian cancer (OC). A Danish cohort study showed a significant increased risk of OC among women with E (SIR (95%CI): 1.34(1.16-1.55)), especially the subtypes endometrioid and clear cell which is in line with international data.

In a systematic review, we found that endometriosis associated ovarian cancers (EAOC) were related to nulliparity, E-diagnosis >45 years of age, endometrioma >9 cm, hyperoestrogenism and/or cysts with solid compartments. A final recommendation of e.g., screening was not possible. However, our results suggest that a subgroup of women with E are in increased risk of EAOC and can be identified through a risk profile.

AIM:

1. To validate the endoemtriosis diagnosis in the Danish National Patient Register in the periode 1995-2018

2. To identify risk factors of developing endometriosis associated ovarian cancer among women diagnosed with endometriosis through the danish national registers in the following categories:

-- Fertility and reproductive related exposures

-- Pelvic and abdominal (incl renal) comorbidity (non-autoimmune) including registered surgical procedures

-- Pelvic and abdominal (incl renal) autoimmune comorbidity

-- Family medical history

3. To identify EAOC specific risk factors among women diagnosed with ovarian cancer. This will be a questionnaire survey.

Description of the cohort

The cohort consistens of women diagnosed with endometriosis and/or ovarian cancer.

A questionnaire will be sent in e-boks to women diagnosed with ovarian cancer stage I-II.

Data and biological material

This project includes data from

1. The National Danish Registers including The National Patient Registry, The Danish Civil Registration system, The Danish Cancer Register and The Medical Birth Register.

2. Questionnaire data

Collaborating researchers and departments

Department of Gynecology and Obstetrics, Odense University Hospital, Svendborg Sygehus, Denmark

• Jan Blaakaer, M.D. DMSc.
• Tine Henrichsen Schnack, M.D. PhD
• Martin Rudnicki, M.D., DMSc

Department of Gynecology and Obstetrics, Aarhus University Hospital, Denmark

• Axel Forman, MD DMSc.

Center for Clinical Epidemiology and Research Unit of Clinical Epidemiology Odense University Hospital, Svendborg Sygehus, Denmark

• Bente Mertz Nørgård, MD, DMSc
• Jan Nielsen, Biostatistiker og adjunkt, Cand. Scient, Ph.d.

Publications associated with the project

Thomsen LH, Schnack TH, Buchardi K, Hummelshoj L, Missmer SA, Forman A, et al. Risk factors of epithelial ovarian carcinomas among women with endometriosis: a systematic review. Acta Obstet Gynecol Scand. 2017;96(1):761-78.