What to Know About Ovarian Cancer Epidemiology

Medically Reviewed by Sabrina Felson, MD on July 27, 2022
5 min read

Ovarian cancer begins in the ovaries, fallopian tubes, or peritoneum. There are two ovaries, which release eggs and produce the hormones estrogen and progesterone. The fallopian tubes connect the ovaries to the uterus. When an ovary releases an egg, it travels through the fallopian tube to the uterus.

Ovarian cancer includes fallopian tube cancer because it can be hard to tell where the cancer started. In fact, doctors have recently learned that most ovarian cancers actually begin at the ends of the fallopian tubes where they meet the ovaries, rather than in the ovary itself.

Peritoneal cancer is also included as ovarian for the same reason, and because it is relatively rare. The peritoneum is tissue that lines most of the organs in the abdomen, including the uterus, ovaries, fallopian tubes, bladder, and rectum, plus the abdomen itself. Because the peritoneum, ovaries, and fallopian tubes are so close together, cancer is often in all three places by the time it’s diagnosed.

Epidemiology studies how a disease or health issue affects certain groups of people. Learning more about ovarian cancer epidemiology can help doctors come up with more targeted treatments for the disease.

Doctors don’t know the exact cause of ovarian cancer, but they do know some factors that make a person more likely to get it.

  • Family history. People who have a family history of breast cancer or ovarian cancer are at higher risk of ovarian cancer.
  • Gene changes. Most commonly known as the breast cancer genes, people with abnormal BRCA1 or BRCA2 genes are at higher risk for ovarian cancer. People of Ashkenazi Jewish descent are more likely to have these changed genes. In fact, the gene changes are 10 times more common in people of that heritage than in the general U.S. population.
  • Age. A person can be diagnosed with ovarian cancer at any age. But, it’s rare in women younger than 40. And more than half of people with the disease are older than 63.
  • Race. White and Hispanic women are more likely to develop ovarian cancer, followed by Asian and Pacific Island women, and then Black women. American Indian/Alaska native ethnicity have the lowest number of cases.
  • Familial syndrome. Women with certain inherited conditions are at higher risk of ovarian cancer. Among these are:
    • Hereditary nonpolyposis colon cancer (HNPCC)
    • Peutz-Jeghers syndrome – a rare condition that causes growths in the stomach and intestine when you’re a teenager
    • MUTYH-associated polyposis – a condition that causes growths in the colon and small intestine
  • Obesity. New studies show people who were obese in early adulthood may be at higher risk of getting ovarian cancer. That doesn’t include people who gained weight later in their lives.
  • Childbearing. Women who have used fertility treatment (in vitro fertilization), have never had a child, or had their first child after age 35 may be at higher risk of ovarian cancer.

Ovarian or fallopian tube cancer is classified based on how the cancer cells look under a microscope. There are three main types of tumors:

  • Epithelial tumors. This is the most common type of ovarian cancer. You may hear it called high-grade serous carcinoma. Under a microscope these cells look similar to the cells that line the fallopian tubes.
  • Germ cell tumors. This cancer starts in the cells in the ovaries that produce eggs. It’s not very common, but it most often affects women younger than 29.
  • Sex cord stromal tumors. This rare type of cancer happens when tumors form in the connective tissue that holds the ovaries together.

Ovarian cancer is often diagnosed at later stages, mainly because obvious symptoms happen at more advanced stages. Ovarian cancer can be stage I through IV. Your doctor may also give the cancer a grade. Grade refers to how the cancer cells look compared to healthy cells and indicates how quickly the cancer is likely to spread.

Symptoms of ovarian cancer are not specific, and can also point to many other noncancerous health issues. You might not even have symptoms at early stages. But later on, you might have:

  • Abdominal pain or bloating
  • Urinary issues, like always feeling like you have to pee or going to the bathroom a lot
  • Fatigue
  • Back pain
  • Stomach issues, including constipation or an upset stomach
  • Changes in your period, like heavier bleeding or bleeding at times other than your normal cycle

Plus, no effective ovarian cancer screening tests exist to detect the cancer early.

Survival rates are different, depending on your cancer’s stage and your race.

Survival differences based on race, ethnicity

White women have the highest rate of death from ovarian cancer. They also get it more than women of other races and ethnicities. But Black women have the second-highest rate of death even though they have fewer cases.

Black women are more likely to be diagnosed with aggressive ovarian tumors, not respond to therapy, and have the disease come back after treatment. They are also more likely to be diagnosed with less common types of ovarian cancer.

Survival based on stage

Ovarian cancer is the leading cause of death from female reproductive cancers. Survival rates are lower than with many other types of cancer. One reason is because it’s often diagnosed at a later stage. Only about 20% of ovarian cancers are detected at an early stage. But when they are, the survival rate is very high: about 94%.

Keep in mind that ovarian cancer statistics are broad estimates based on outcomes of large numbers of people. They don’t predict individual cases, because the disease and response to treatment varies greatly among people.

The overall relative 5-year survival rate for ovarian cancer is 49.7%. This is the percentage of people in a study (or treatment group) who are alive 5 years after they were diagnosed or treated (whether the cancer has returned or not).

Within that overall number, the ovarian cancer survival rate by stage varies. Here are 5-year survival rates by stage:

  • Localized, the cancer hasn’t spread beyond the initial tumor location: 93.1%
  • Regional, the cancer has spread to lymph nodes: 74.2%
  • Distant, the cancer has spread to other organs: 30.8%
  • Unknown, stage is not known: 28.2%

Ovarian cancer diagnoses have been dropping over the past two decades. Doctors are still learning more about the disease and how to treat it. If you have symptoms or risk factors of ovarian cancer, make an appointment with your doctor right away.