Ovarian cancer is a disease in which cancer cells form in the tissues of the ovaries. The ovaries are two almond-shaped organs, located on either side of the uterus. They produce female hormones and eggs.
Ovarian cancer is hard to detect in its early stages and can spread quickly. Ovaries contain many small glands that produce and release an egg each month during a woman’s menstrual cycle. The ovary also produces female hormones, such as estrogen and progesterone, that control a woman’s cycle, fertility, and pregnancy.
In most cases, ovarian cancers begin as abnormal growths in the cells lining the surface of the ovary. These abnormal cells may eventually become cancerous if they continue to grow unchecked or if they invade other tissues or organs of the body.
Table of Contents
- How common is ovarian cancer?
- Risk factors of ovarian cancer
- Types of ovarian cancer
- Symptoms of ovarian cancer
- Treatment for ovarian cancer
How common is ovarian cancer?
About 6 percent of women will develop ovarian cancer in their lifetime. That’s about 1 out of every 78 women. Ovarian cancer is more common in older women and among those who have never been pregnant or who haven’t had children.
The American Cancer Society reports that around 22,000 new cases of ovarian cancer were diagnosed in 2021, and almost 14,000 women lost their lives. Ovarian cancer accounts for about 2 percent of all cancers among women in the United States.
The good news is that many women with ovarian cancer can be cured (1). But you need to get treatment as soon as possible after symptoms begin.
Risk factors of ovarian cancer
On average, the five-year survival rate (2) for ovarian cancer is about 35%. The survival rate depends on many factors, including how advanced the disease is when it’s diagnosed, a person’s general health, and whether they choose surgery or chemotherapy as their primary treatment method.
Ovarian cancer is twice as common in women over age 63 (3), but it can also occur at younger ages. The following factors increase your risk of ovarian cancer:
Personal medical history
Personal medical history is one of the most important factors that can increase your risk of ovarian cancer. If you have one or more close relatives who have had breast or ovarian cancer, this increases your risk of developing cancer.
If you have no family history of these cancers but do have a personal medical history of endometrial cancer (cancer of the lining of the uterus), you may also be at increased risk for developing ovarian cancer.
Having a personal medical history of any other types of cancers, including skin cancers, lung and liver cancers, prostate cancer, and pancreatic cancer, makes it unlikely that they will increase your risk for developing ovarian cancer unless there are multiple diagnoses in different sites in your family.
Researchers have identified several genes that increase the risk for some types of ovarian cancer. These include:
BRCA1 and BRCA2 (4): These genes make proteins that repair DNA. Mutations in these genes can lead to an increased risk of breast and ovarian cancers. Women with BRCA1 or BRCA2 mutations have a lifetime risk of developing breast or ovarian cancer as high as 40% or even higher.
The risk of ovarian cancer increases with each pregnancy and decreases after menopause. Reproductive history may also increase or decrease the risk depending on the number of pregnancies and whether or not they were full-term (duration).
Women who have had two full-term pregnancies have a lower risk than those who have never been pregnant, while women who have had four or more full-term pregnancies have an increased risk compared with those who have never been pregnant.
The risk of ovarian cancer is higher in women who are Caucasian, African-American, or Hispanic compared to Asian women.
African-American women have a greater risk of developing ovarian cancer than Caucasian women. The risk for Hispanic women is about 40% higher than it is for Caucasian women.
Asian women are at lower risk of developing ovarian cancer than other ethnicities but it does still occur. The risk is particularly low if they were born in Asia and have never lived outside it.
Age is the biggest risk factor for developing ovarian cancer. The average age at diagnosis is 63, but it’s not uncommon to find women under 40 with the disease. The risk of ovarian cancer increases as you get older because your ovaries produce more eggs and have a greater chance of developing genetic changes that may lead to cancer.
The risk of ovarian cancer increases with increasing body size (5). The risk of ovarian cancer in non-Hispanic white women is higher than expected among those who are underweight or obese.
A new study published in Cancer, a journal of the American Cancer Society, found that the increased risk of ovarian cancer among women who were overweight or obese was not because of their weight alone. The researchers said that further studies are needed to understand why this is happening.
Types of ovarian cancer
Ovarian cancer can start in any part of an ovary, but most cancers develop in the egg-producing cells called follicles. Cancers that begin in the fluid-filled spaces inside the ovary (the interstitial cells) are less common but more likely to spread quickly than ovarian cancers that begin in other tissues.
Some ovarian tumors spread (metastasize) to other parts of the body, but most do not. If cancer does spread to other organs, it is usually found in distant organs such as the liver or lungs. Ovarian cancers rarely spread directly from one organ to another without first spreading through the bloodstream or lymphatic system.
Epithelial ovarian cancer
Epithelial ovarian cancer (6) begins in the cells that line the surface of the ovary. This type accounts for about 90% of all ovarian cancers.
The majority of epithelial ovarian cancers are either serous or endometrioid carcinomas. These types of tumors begin in the cells that line the outer surface of the ovary and grow slowly, often for years before they are diagnosed (7).
Serous carcinomas appear as sheet or sheet-like areas within the ovary. Because they grow slowly, they tend to be more advanced when they’re diagnosed. They are also more likely to spread during treatment, so you may need more treatment if you have this type of cancer than if you have another type.
Endometrioid carcinomas appear as solid areas within the ovary and have a higher risk of spreading beyond the ovaries than serous carcinomas do.
Epithelial ovarian cancers can also be classified by their grade (how aggressive they are), stage (how far they’ve spread), and histologic subtype (what kind of cell they look like under a microscope).
Germ cell ovarian cancer
Germ cell tumors start within germ cells before birth or very soon after, so they can be found in children and adolescents. These tumors account for about 8% of all ovarian cancers, but most cases occur in women in their 40s.
Germ cell ovarian cancer, also known as ovarian sex cord-stromal tumors, is a rare type of cancer that begins in the cells that produce eggs. Germ cell tumors typically occur in women between the ages of 20 and 40 years old.
The cause of germ cell tumors is unknown. Some research suggests they may be related to genetic changes (mutations). These mutations may be inherited or acquired during a person’s lifetime.
Germ cell tumors can develop in any part of the body but are most common in the ovaries. These tumors are often diagnosed at an early stage because they cause symptoms, such as pelvic pain and swelling, that is easily recognized by patients or their doctors.
Treatment for germ cell ovarian cancer (8) depends on several factors, including its stage (extent) and whether it has spread from the ovaries to other areas of your body. Treatment options include surgery (removing part or all of the affected tissue), chemotherapy (drugs that kill cancer cells), and radiation therapy (high-energy x-rays).
Stromal ovarian cancer
Stromal/stroma-like tumors contain both epithelial and stromal (connective tissue) cells, but they’re generally not classified as either type alone because they don’t fit neatly into either category.
Stromal ovarian cancer refers to a type of cancer that starts in the stroma, which is the tissue surrounding the ovary. Stromal ovarian cancer is rare but treatable (9), accounting for less than 2% of all ovarian cancers.
Symptoms of ovarian cancer
As ovarian cancer is often diagnosed at an advanced stage, it is not always possible to identify the symptoms early. However, some symptoms are common in early ovarian cancers and they may include:
1. Frequent bloating
One of the most common signs of ovarian cancer is a feeling of bloating regularly. This can be accompanied by pain in the lower abdomen, which is often mistaken for menstrual cramps. Some women may also experience constipation or diarrhea.
Although it’s normal to feel bloated after eating, some women experience this sensation more frequently than others. If you’re experiencing bloating that’s accompanied by pain or other unusual symptoms, it’s important to see your doctor to rule out ovarian cancer as soon as possible.
2. Lower back pain
Pain in the lower back or pelvis is often one of the first signs of ovarian cancer. It may be worse after periods or bowel movements, and it can be persistent or come and go.
Pain in the pelvis or abdomen usually spreads to the groin area. The pain may be constant or come and go, but it may feel like a dull ache rather than sharp pain. It may worsen with exertion, such as coughing, sneezing, or lifting heavy objects.
Constipation is a common symptom of ovarian cancer. Constipation occurs when stool in the colon becomes hard and dry due to a lack of water and fiber.
This may be due to the tumor putting pressure on the colon or rectum. The tumor may also cause the muscles in your intestines to contract, which can make it difficult for stool to pass through.
Stool changes related to ovarian cancer include having less frequent bowel movements than usual, feeling bloated or full after eating, straining when trying to have a bowel movement, and having fewer normal bowel movements than usual.
Ovarian cancer symptoms can include fatigue. The fatigue often comes on gradually and may be accompanied by other ovarian cancer symptoms, such as loss of appetite, bloating, and indigestion.
The symptoms of ovarian cancer are vague (10) and not specific enough to bring about a diagnosis. Many women attribute their symptoms to stress or aging. As a result, most wait too long before seeking treatment for ovarian cancer.
5. Pain or discomfort in the abdomen or pelvis
Another common symptom of ovarian cancer is abdominal pain. The cancer usually does not cause any pain in these areas until it has developed advanced stages.
The level of pain can vary widely and many people with ovarian cancer don’t even realize they have it until they’re diagnosed at stage 3 or 4. This is why regular screening tests are important as they can detect the disease before symptoms appear.
6. Quickly feeling full when eating
Many women feel full after a meal and can’t eat more than half of what they usually would. Some feel sick if they eat too much. They also may have diarrhea, nausea, and vomiting after eating.
Feeling full quickly or bloated for no reason are common signs of an enlarged stomach caused by fluid buildup from an ovarian cyst or tumor pressing on nearby organs or other structures in the abdomen.
7. A frequent, urgent need to urinate
The most common symptom of ovarian cancer is a frequent, urgent need to urinate. This can be caused by an enlarged pelvic tumor pressing on the bladder or ureter which is the tube that connects the kidneys and bladder.
While most women do not experience frequent urination before being diagnosed with ovarian cancer, it’s still important for women to pay attention to these symptoms as well as other changes in bowel habits.
8. A change in the menstrual cycle
The symptoms of ovarian cancer vary from woman to woman, and some women don’t have any symptoms at all. Many doctors recommend women get screened for ovarian cancer starting at age 35, but it’s important to know what symptoms you should be looking for.
A change in the menstrual cycle is one sign of ovarian cancer that many women don’t give a lot of attention to. It’s common to have an irregular menstruation cycle while approaching menopause, but it’s always safe to talk to a doctor when this happens.
9. Difficulty eating
Many women, especially those who are busy or stressed, often experience nausea and an upset stomach. While occasional difficulty eating is nothing to worry about, it can be a sign of ovarian cancer.
Ovarian cancer is often an insidious disease, as it may not cause any difficulty eating until it has spread to other organs. In its early stages, ovarian cancer does not usually present with such a symptom.
Treatment for ovarian cancer
Treatment options vary depending on the stage and type of a woman’s ovarian cancer. Surgery is often used to treat early-stage cancers. For advanced stages, chemotherapy and hormonal therapy are used along with surgery.
Surgery to remove an ovarian tumor is called a laparotomy (11). Depending on the location and size of the tumor, your doctor may perform a laparoscopic or robotic approach to removing your ovaries.
During a laparotomy, your surgeon makes a long incision in your abdomen, usually horizontally. This allows him or her to access the organs inside your abdomen and remove any tumors found there.
If you have cancer that has spread beyond the ovaries into other parts of your body, such as the lymph nodes, this procedure may be used to surgically remove those areas as well. But if all evidence of cancer has been removed, there’s no need for further treatment.
Chemotherapy may be used to shrink a tumor before surgery, or it may be used after surgery to kill any remaining cancer cells. It’s also given after surgery to help lower the risk of ovarian cancer coming back.
Chemotherapy may be used alone or with other treatments for ovarian cancer. It is often used with radiation therapy to treat ovarian cancer that has spread to other parts of the body.
The five-year survival rate for women with early-stage ovarian cancer is 92%. For women with advanced-stage disease, the five-year survival rate is about 15%.
Hopefully, reproductive cancers, like ovarian cancer, will be much less of a threat in the future. Until that day comes, there are steps you can take to improve your chances for early detection. The earlier it is detected, the better your odds are of beating the disease, so never hesitate to ask questions about symptoms or risks when visiting your doctor.