Study Finds Increased Ovarian Cancer Risk in Women with Ovarian Endometriomas and Deep Infiltrating Endometriosis

"Women with endometriosis have a 4.2-fold increased risk of developing ovarian cancer compared to those without the condition. Specifically, women with ovarian endometriomas and/or deep infiltrating endometriosis face a 9.7-fold higher risk," the researchers reported in JAMA.

Associations between endometriosis subtypes and ovarian cancer histotypes were much greater for type I (clear cell, endometrioid, mucinous, and low-grade serous) compared with type II (high-grade serous) ovarian cancers," they wrote.

Endometriosis is linked to a higher risk of ovarian cancer; however, the relationships between different endometriosis subtypes and specific ovarian cancer histotypes are not well understood. To fill this knowledge gap, Mollie E. Barnard, Huntsman Cancer Institute, University of Utah, Salt Lake City, and colleagues aimed to evaluate the associations of endometriosis subtypes with the incidence of ovarian cancer, both overall and by histotype.

For this purpose, the researchers conducted a population-based cohort study using data from the Utah Population Database. The cohort was created by matching 78,893 women with endometriosis to five women without the condition in a 1:5 ratio.

Endometriosis cases were identified via electronic health records and categorized as ovarian endometriomas, superficial endometriosis, deep infiltrating endometriosis, or others.

Estimated adjusted hazard ratios (aHRs) and adjusted risk differences (aRDs) per 10,000 women were calculated for overall ovarian cancer, type I ovarian cancer, and type II ovarian cancer, comparing women with each endometriosis type to those without the condition. The models accounted for sociodemographic factors, reproductive history, and previous gynecologic surgeries.

The following were the key findings of the study:

• In the Utah-based cohort, the mean age at first endometriosis diagnosis was 36 years. There were 597 women with ovarian cancer.
• Ovarian cancer risk was higher among women with endometriosis compared with women without endometriosis (aHR, 4.20; aRD, 9.90), and the risk of type I ovarian cancer was especially high (aHR, 7.48; aRD, 7.53).
• Ovarian cancer risk was highest in women with deep infiltrating endometriosis and/or ovarian endometriomas for all ovarian cancers (aHR, 9.66; aRD, 26.71), type I ovarian cancer (aHR, 18.96; aRD, 19.57), and type II ovarian cancer (aHR, 3.72; aRD, 2.42).

The findings showed a markedly increased risk of ovarian cancer among women with ovarian endometriomas and/or deep infiltrating endometriosis.

"This population may benefit from counseling concerning ovarian cancer risk and prevention and could be an important population for targeted screening and prevention studies," the researchers concluded.

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