Endometriosis Types and Ovarian Cancer Risk (NIH)

Endometriosis and Ovarian Cancer Risk

Overview

  • Research indicates that certain types of severe endometriosis are associated with a significantly increased risk of ovarian cancer.

  • Further research involving large, diverse populations is necessary to confirm these findings.

  • The goal is to improve ovarian cancer screening and develop prevention strategies.

Endometriosis

  • Endometriosis: A condition where tissue similar to the lining of the uterus grows outside the uterus.

  • Common symptoms: pelvic pain and infertility.

  • Recent studies have linked endometriosis to a higher risk of ovarian cancer.

Types of Endometriosis

  • Three main subtypes:

    • Superficial Endometriosis:

      • Occurs mainly on the mucous membrane around the pelvic cavity.

    • Deep Infiltrating Endometriosis:

      • Affects organs near the uterus, such as the ovaries, bladder, and bowels.

    • Endometriomas:

      • Cysts that form within the ovaries.

Study on Endometriosis Subtypes and Ovarian Cancer Risk

  • Researchers: Led by Dr. Karen Schliep at the University of Utah.

  • Data source: Utah Population Database, which links health records from over 11 million people.

  • Study population:

    • Over 78,000 women aged 18 to 55 with an endometriosis diagnosis.

    • Compared to a matched group of almost 380,000 women without endometriosis.

  • Outcomes:

    • Nearly 600 women developed ovarian cancer.

    • Considered sociodemographic factors, reproductive histories, and surgical histories.

  • Average age of endometriosis diagnosis: Around 36 years.

Study Results

  • Overall, women with endometriosis had more than 4 times the risk of ovarian cancer compared to those without endometriosis.

  • This translates to approximately 10 more cases per 10,000 women.

  • Risk variation: Ovarian cancer risk differs with endometriosis subtype.

    • Deep infiltrating endometriosis.

    • Ovarian endometriomas.

    • Risk was more than 9 times that of women without endometriosis for severe subtypes.

  • Type I cancer: Much of the increased cancer risk in women with endometriosis was due to type I cancer, which tends to grow more slowly and cause fewer symptoms than type II cancer.

    • Women with endometriosis were 7.5 times more likely to develop type I cancer than women without endometriosis.

    • Among women with severe endometriosis subtypes, the risk of type I cancer was almost 19 times greater than in women without endometriosis.

Researcher's Perspective

  • Dr. Schliep emphasizes the importance of providing women with the right information to make informed decisions about their treatment options in consultation with their physicians.

Funding

  • The study was partly funded by NIH’s National Cancer Institute (NCI), National Heart, Lung, and Blood Institute (NHLBI), and National Institute on Aging.

  • Additional support from the University of Utah, Utah Department of Health and Human Services, US Centers for Disease Control and Prevention, Huntsman Cancer Foundation, Doris Duke Foundation, and American Heart Association.

Additional Information

  • Further study is needed to understand how specific types of endometriosis might give rise to different ovarian cancers.

  • Such knowledge could lead to new approaches for prevention and treatment.

The purpose of this article is to highlight the association between certain types of severe endometriosis and an increased risk of ovarian cancer. It emphasizes the need for further research involving large and diverse populations to confirm these findings, aiming to improve ovarian cancer screening and develop prevention strategies. The article details the characteristics of endometriosis, various types, and pertinent research findings related to the risk of ovarian cancer, as well as the researchers' perspectives and funding sources.

The tissue of endometriosis, which resembles the lining of the uterus, grows outside of the uterus and can lead to an increased risk of cancer through several mechanisms:

  • Chronic Inflammation: The presence of endometrial tissue in locations outside the uterus can lead to chronic inflammation, which is known to promote cancer development. Inflammation can create an environment that encourages the formation and growth of tumors.

  • Hormonal Environment: Endometriosis can create hormonal imbalances that may promote the growth of certain cancers. The ectopic endometrial tissue is influenced by hormones, particularly estrogen, which can drive the proliferation of both endometrial tissue and ovarian cancer cells.

  • Genetic Alterations: Women with severe endometriosis may experience genetic changes that predispose them to cancer. The interactions between endometriosis tissue and the surrounding cells could lead to mutations that contribute to cancer development.

  • Type I Cancer Association: Much of the increased cancer risk in women with endometriosis has been linked to type I cancer, which tends to grow more slowly and may have a different pathology compared to type II cancer. Reports indicate that women with endometriosis were 7.5 times more likely to develop type I cancer than those without endometriosis, and this risk was almost 19 times greater among women with severe endometriosis subtypes.

Further research is needed to fully understand the biological mechanisms linking endometriosis with cancer development, including how specific types of endometriosis may lead to different cancer types.