Endometriosis can raise a person’s risk of ovarian cancer, but only slightly. The majority of people with endometriosis will never develop this type of cancer. Additionally, endometriosis treatments can sometimes help lower ovarian cancer risk.

Endometriosis and Ovarian Cancer

About 1 in 10 women have endometriosis. In this condition, the endometrium (tissue that is normally found in the lining of the uterus) grows in various locations, such as the ovaries, fallopian tubes, and other organs in the pelvis or abdomen. Endometriosis often leads to pelvic pain, urination changes, constipation, ovarian cyst formation, and infertility.

How Endometriosis Affects Ovarian Cancer Risk

About 1.2 percent of women within the general population are diagnosed with ovarian cancer at some point in their lives. People with endometriosis develop ovarian cancer at slightly higher rates.

Some research has shown that 1.8 percent of women with endometriosis will develop ovarian cancer — only a very small increased risk compared to other women. Other studies have reported that ovarian cancer is diagnosed in up to 17 percent of women with endometriosis. Reasons for these varying results may be that researchers have measured this effect within different groups of women, using different studies and analyzing data in different ways.

Certain factors may make someone with endometriosis more likely to develop ovarian cancer, including:

• Older age
• Having higher levels of a protein called CA-125 in the blood
• Having endometriosis for more than five years
• Having very large endometriosis lesions (tissue growths)

Ultimately, endometriosis leads to a small increased risk of ovarian cancer. The majority of people with endometriosis don’t develop cancer.

Endometriosis and Ovarian Cancer Prognosis

When people with endometriosis develop ovarian cancer, they are more likely to have a good prognosis (outlook).

There are several different types of ovarian cancer. Women with endometriosis are more likely to develop two types: endometrioid carcinoma and clear cell carcinoma. These types of ovarian cancer are more likely to be caught early and have a better outlook compared with other types. This aspect doesn’t usually translate to endometriosis-derived cancer, as by definition, it is outside the organs and in the peritoneal cavity. Additionally, women with endometriosis who develop ovarian cancer are usually younger, and cancer is diagnosed at an earlier stage, making their chance of a good prognosis higher.

Endometriosis Treatments and Cancer Risk

Although endometriosis can raise a person’s chances of developing ovarian cancer, some treatments for endometriosis can also lower the risk.

Hormone Medications

Taking medications that stabilize hormone levels sometimes reduces endometriosis symptoms. Hormone medications include birth control pills, patches, implants, and intrauterine devices (IUDs). Hormonal birth control can cut a person’s risk of ovarian cancer in half.

Surgery

Some people with endometriosis have surgery to remove the extra endometrial tissue. This type of surgery can help reduce some of the symptoms caused by endometriosis. Other surgical options involve removing reproductive organs:

• Hysterectomy — Removal of the uterus
• Salpingectomy — Removal of the fallopian tubes
• Oophorectomy — Removal of the ovaries

Many doctors no longer recommend surgery that removes organs. This approach does not always help relieve endometriosis symptoms. Additionally, it comes with risks. Women who have a hysterectomy can no longer get pregnant. An oophorectomy will cause menopause for those who are still having their periods. Early menopause leads to a higher risk of heart disease, metabolic disease, and early death.

Although removing the ovaries and fallopian tubes will prevent ovarian cancer, the chances of developing this cancer are not very high. Many doctors think that the risks are not worth the benefits.

Can You Prevent Ovarian Cancer?

It’s not possible to completely prevent ovarian cancer. However, you can reduce your risk by eliminating certain risk factors, being aware of the signs and symptoms of ovarian cancer, and having regular gynecologist visits.

Reducing Other Risk Factors

Several factors besides endometriosis affect your risk of ovarian cancer. You can’t change some risk factors, such as your age or the genes you have. However, you have more control over others. To reduce your cancer risk, some lifestyle changes may help:

• Eat a balanced diet containing a variety of foods and nutrients.
• Limit how much alcohol you drink.
• Exercise regularly.
• Keep your weight at a healthy level.
• Avoid smoking.
• Don’t use hormone replacement therapy after going into menopause.

Knowing the Symptoms of Ovarian Cancer

People who catch their ovarian cancer early often have better outcomes. You can reduce your risk of a poor prognosis by knowing the symptoms of ovarian cancer and quickly checking on any health changes.

The most common ovarian cancer symptoms to watch out for include:

• Stomach pain
• Bloating
• More frequent urination
• Feeling full after eating only a little

Keeping Regular Doctor’s Visits

Regular pelvic exams can help your doctor make sure your reproductive system is healthy. However, pelvic exams don’t always catch early-stage ovarian cancer.

Screening tests may sometimes detect other types of cancer while they are in the early stages. However, screening tests are not that effective for ovarian cancer. Screening may include an ultrasound to view the ovaries or a blood test to look for CA-125. These tests don’t always work well to catch ovarian cancer early, and they often uncover other abnormalities that end up not being cancer. These findings sometimes result in people undergoing extra procedures that aren’t necessary and carry a risk of causing injury.

If you are worried about ovarian cancer risk, talk to your doctor. Your doctor can help you understand your risk level based on your personal and family history and may be able to recommend other strategies for managing risk. Keep in mind that the risk of ovarian cancer for people with endometriosis is not much different than it is for other people.

Talk With Others Who Understand

MyOvarianCancerTeam is the social network for people with ovarian cancer and their loved ones. Members come together to ask questions, give advice, and share their stories with others who understand life with ovarian cancer.

Are you living with ovarian cancer or endometriosis? Share your experiences in the comments below, or start a conversation by posting on MyOvarianCancerTeam.