The exact causes of ovarian cancer are not known. However, studies show that the following factors may increase the chance of developing this disease:
- Family history. First-degree relatives (mother, daughter, sister) of a woman who has had ovarian cancer are at increased risk of developing this type of cancer themselves. The likelihood is especially high if two or more first-degree relatives have had the disease. The risk is somewhat less, but still above average, if other relatives (grandmother, aunt, cousin) have had ovarian cancer. A family history of breast or colon cancer is also associated with an increased risk of developing ovarian cancer.
- Age. The likelihood of developing ovarian cancer increases as a woman gets older. Most ovarian cancers occur in women over the age of 50, with the highest risk in women over 60.
- Childbearing. Women who have never had children are more likely to develop ovarian cancer than women who have had children. In fact, the more children a woman has had, the less likely she is to develop ovarian cancer.
- Personal history. Women who have had breast or colon cancer may have a greater chance of developing ovarian cancer than women who have not had breast or colon cancer.
- Fertility drugs. Drugs that cause a woman to ovulate may slightly increase a woman’s chance of developing ovarian cancer. Researchers are studying this possible association.
- Talc. Some studies suggest that women who have used talc in the genital area for many years may be at increased risk of developing ovarian cancer.
- Hormone replacement therapy (HRT). Some evidence suggests that women who use HRT after menopause may have a slightly increased risk of developing ovarian cancer.
As we learn more about what causes ovarian cancer, we may also learn how to reduce the chance of getting this disease. Some studies have shown that breast feeding and taking birth control pills (oral contraceptives) may decrease a woman’s likelihood of developing ovarian cancer. These factors decrease the number of times a woman ovulates, and studies suggest that reducing the number of ovulations during a woman’s lifetime may lower the risk of ovarian cancer.
Women who have had an operation that prevents pregnancy (tubal ligation) or have had their uterus and cervix removed (hysterectomy) also have a lower risk of developing ovarian cancer. In addition, some evidence suggests that reducing the amount of fat in the diet may lower the risk of developing ovarian cancer.
Women who are at high risk for ovarian cancer due to a family history of the disease may consider having their ovaries removed before cancer develops (prophylactic oophorectomy). This procedure usually, but not always, protects women from developing ovarian cancer. The risks associated with this surgery and its side effects should be carefully considered. A woman should discuss the possible benefits and risks with her doctor based on her unique situation.
Having one or more of the risk factors mentioned here does not mean that a woman is sure to develop ovarian cancer, but the chance may be higher than average. Women who are concerned about ovarian cancer may want to talk with a doctor who specializes in treating women with cancer: a gynecologist, a gynecologic oncologist, or a medical oncologist. The doctor may be able to suggest ways to reduce the likelihood of developing ovarian cancer and can plan an appropriate schedule for checkups.
Detecting Ovarian Cancer
The sooner ovarian cancer is found and treated, the better a woman’s chance for recovery. But ovarian cancer is hard to detect early. Many times, women with ovarian cancer have no symptoms or just mild symptoms until the disease is in an advanced stage. Scientists are studying ways to detect ovarian cancer before symptoms develop. They are exploring the usefulness of measuring the level of CA-125, a substance called a tumor marker, which is often found in higher-than-normal amounts in the blood of women with ovarian cancer. They also are evaluating transvaginal ultrasound, a test that may help detect the disease early. The Cancer Information Service can provide information about this research.
Ovarian cancer often shows no obvious signs or symptoms until late in its development. Signs and symptoms of ovarian cancer may include:
- General abdominal discomfort and/or pain (gas, indigestion, pressure, swelling, bloating, cramps)
- Nausea, diarrhea, constipation, or frequent urination
- Loss of appetite
- Feeling of fullness even after a light meal
- Weight gain or loss with no known reason
- Abnormal bleeding from the vagina
These symptoms may be caused by ovarian cancer or by other, less serious conditions. It is important to check with a doctor about any of these symptoms.
Diagnosing Ovarian Cancer
To help find the cause of symptoms, a doctor evaluates a woman’s medical history. The doctor also performs a physical exam and orders diagnostic tests. Some exams and tests that may be useful are described below:
- Pelvic exam includes feeling the uterus, vagina, ovaries, fallopian tubes, bladder, and rectum to find any abnormality in their shape or size. (A Pap test, a good test for cancer of the cervix, is often done along with the pelvic exam, but it is not a reliable way to find or diagnose ovarian cancer.)
- Ultrasound refers to the use of high-frequency sound waves. These waves, which cannot be heard by humans, are aimed at the ovaries. The pattern of the echoes they produce creates a picture called a sonogram. Healthy tissues, fluid-filled cysts, and tumors look different on this picture.
- CA-125 assay is a blood test used to measure the level of CA-125, a tumor marker that is often found in higher-than-normal amounts in the blood of women with ovarian cancer.
- Lower GI series, or barium enema, is a series of x-rays of the colon and rectum. The pictures are taken after the patient is given an enema with a white, chalky solution containing barium. The barium outlines the colon and rectum on the x-ray, making tumors or other abnormal areas easier to see.
- CT (or CAT) scan is a series of detailed pictures of areas inside the body created by a computer linked to an x-ray machine.
- Biopsy is the removal of tissue for examination under a microscope. A pathologist studies the tissue to make a diagnosis. To obtain the tissue, the surgeon performs a laparotomy (an operation to open the abdomen). If cancer is suspected, the surgeon performs an oophorectomy (removal of the entire ovary). This is important because, if cancer is present, removing just a sample of tissue by cutting through the outer layer of the ovary could allow cancer cells to escape and cause the disease to spread.
- If the diagnosis is ovarian cancer, the doctor will want to learn the stage (or extent) of disease. Staging is a careful attempt to find out whether the cancer has spread and, if so, to what parts of the body. Staging may involve surgery, x-rays and other imaging procedures, and lab tests. Knowing the stage of the disease helps the doctor plan treatment.
Treatment for Ovarian Cancer
Treatment depends on a number of factors, including the stage of the disease and the general health of the patient. Patients are often treated by a team of specialists. The team may include a gynecologist, a gynecologic oncologist, a medical oncologist, and/or a radiation oncologist. Many different treatments and combinations of treatments are used to treat ovarian cancer.
- Surgery is the usual initial treatment for women diagnosed with ovarian cancer. The ovaries, the fallopian tubes, the uterus, and the cervix are usually removed. This operation is called a hysterectomy with bilateral salpingo-oophorectomy. Often, the surgeon also removes the omentum (the thin tissue covering the stomach and large intestine) and lymph nodes (small organs located along the channels of the lymphatic system) in the abdomen.Staging during surgery (to find out whether the cancer has spread) generally involves removing lymph nodes, samples of tissue from the diaphragm and other organs in the abdomen, and fluid from the abdomen. If the cancer has spread, the surgeon usually removes as much of the cancer as possible in a procedure called tumor debulking. Tumor debulking reduces the amount of cancer that will have to be treated later with chemotherapy or radiation therapy.
- Chemotherapy is the use of drugs to kill cancer cells. Chemotherapy may be given to destroy any cancerous cells that may remain in the body after surgery, to control tumor growth, or to relieve symptoms of the disease.Most drugs used to treat ovarian cancer are given by injection into a vein (intravenously, or IV). The drugs can be injected directly into a vein or given through a catheter, a thin tube. The catheter is placed into a large vein and remains there as long as it is needed. Some anticancer drugs are taken by mouth. Whether they are given intravenously or by mouth, the drugs enter the bloodstream and circulate throughout the body.Another way to give chemotherapy is to put the drug directly into the abdomen through a catheter. With this method, called intraperitoneal chemotherapy, most of the drug remains in the abdomen.After chemotherapy is completed, second-look surgery may be performed to examine the abdomen directly. The surgeon may remove fluid and tissue samples to see whether the anticancer drugs have been successful.
- Radiation therapy, also called radiotherapy, involves the use of high-energy rays to kill cancer cells. Radiation therapy affects the cancer cells only in the treated area. The radiation may come from a machine (external radiation). Some women receive a treatment called intraperitoneal radiation therapy in which radioactive liquid is put directly into the abdomen through a catheter.
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Possible Side Effects of Treatment
The side effects of cancer treatment depend on the type of treatment and may be different for each woman. Doctors and nurses will explain the possible side effects of treatment, and they can suggest ways to help relieve problems that may occur during and after treatment.
- Surgery causes short-term pain and tenderness in the area of the operation. Discomfort or pain after surgery can be controlled with medicine. Patients should feel free to discuss pain relief with their doctor. For several days after surgery, the patient may have difficulty emptying her bladder and having bowel movements.When both ovaries are removed, a woman loses her ability to become pregnant. Some women may experience feelings of loss that may make intimacy difficult. Counseling or support for both the patient and her partner may be helpful.Also, removing the ovaries means that the body’s natural source of estrogen and progesterone is lost, and menopause occurs. Symptoms of menopause, such as hot flashes and vaginal dryness, are likely to appear soon after the surgery. Some form of hormone replacement therapy may be used to ease such symptoms. Deciding whether to use it is a personal choice; women with ovarian cancer should discuss with their doctors the possible risks and benefits of using hormone replacement therapy.
- Chemotherapy affects normal as well as cancerous cells. Side effects depend largely on the specific drugs and the dose (amount of drug given). Common side effects of chemotherapy include nausea and vomiting, loss of appetite, diarrhea, fatigue, numbness and tingling in hands or feet, headaches, hair loss, and darkening of the skin and fingernails. Certain drugs used in the treatment of ovarian cancer can cause some hearing loss or kidney damage. To help protect the kidneys while taking these drugs, patients may receive extra fluid intravenously.
- Radiation therapy, like chemotherapy, affects normal as well as cancerous cells. Side effects of radiation therapy depend mainly on the treatment dose and the part of the body that is treated. Common side effects of radiation therapy to the abdomen are fatigue, loss of appetite, nausea, vomiting, urinary discomfort, diarrhea, and skin changes on the abdomen. Intraperitoneal radiation therapy may cause abdominal pain and bowel obstruction (a blockage of the intestine).
Several NCI booklets, including Chemotherapy and You, Radiation Therapy and You, and Eating Hints for Cancer Patients, suggest ways for patients to cope with the side effects they experience during cancer treatment.
The Importance of Followup Care
Followup care after treatment for ovarian cancer is important. Regular checkups generally include a physical exam, as well as a pelvic exam and Pap test. The doctor also may perform additional tests such as a chest x-ray, CT scan, urinalysis, complete blood count, and CA-125 assay.
In addition to having followup exams to check for the return of ovarian cancer, patients may also want to ask their doctor about checking them for other types of cancer. Women who have had ovarian cancer may be at increased risk of developing breast or colon cancer.