Study Finds Potential Link Between Endometriosis and Ovarian Cancer

A recent study published in JAMA revealed that women with ovarian endometriomas or deep infiltrating endometriosis face a significantly heightened risk of developing ovarian cancer.

Endometriosis affects approximately 11% of reproductive-aged women, including 50% to 60% of women and teenage girls experiencing pelvic pain and up to 50% of women with infertility. This condition has been associated with various comorbidities, including ovarian, breast, and endometrial cancers, and impacts mental, menstrual, urinary, bowel, and other nonspecific symptoms.

The study, conducted using data from the Utah Population Database (UPDB), aimed to evaluate the association between endometriosis and ovarian cancer incidence. Researchers developed a retrospective cohort, including women aged 18 to 55 years with at least one diagnosis of endometriosis.

The findings revealed an observed endometriosis prevalence of 6.3%, with categories including superficial peritoneal endometriosis, ovarian endometriomas, deep infiltrating endometriosis, ovarian endometriosis, and concurrent deep infiltrating endometriosis. Women with a history of endometriosis were matched 1:5 with unexposed women.

The study found that all ovarian cancer histotypes were more common in women with endometriosis, with adjusted hazard ratios (aHRs) ranging from 2.70 for high-grade serous ovarian cancer to 11.15 for clear cell carcinoma. Overall, the aHR for ovarian cancer in women with endometriosis was 4.20 compared to those without the condition.

Women with deep infiltrating endometriosis or ovarian endometriomas had the highest risk of ovarian cancer. The aHR for deep infiltrating endometriosis was 18.76, and for concurrent deep infiltrating endometriosis and ovarian endometriomas, it was 13.04. The strongest association was found between these endometriosis subtypes and type 1 ovarian cancer, with an aHR of 18.96. However, all endometriosis subtypes were linked to increased risks of both type 1 and type 2 ovarian cancer.

The study identified an excess risk of ovarian cancer in 9.90 women with endometriosis per 10,000. The overall bias-adjusted hazard ratio was 8.29.

These results underscored the significantly increased risk of ovarian cancer among women with endometriosis, prompting the need for further studies to better understand the biological mechanisms underlying these associations.

Reference: Barnard ME, Farland LV, Yan B, et al. Endometriosis Typology and Ovarian Cancer Risk. JAMA. Published online July 17, 2024. doi:10.1001/jama.2024.9210