Ovarian Cancer

What is ovarian cancer?

The American Cancer Society estimates that there will be about 21,500 new cases of ovarian cancer in this country in 2009. About 14,600 women will die this year because of the disease. About two-thirds of women with ovarian cancer are 55 or older. It is slightly more common in white women than in African-American women.

A woman’s risk of getting invasive ovarian cancer during her lifetime is about 1 in 71. Her lifetime chance of dying from invasive ovarian cancer is about 1 in 95. 

What are the symptoms of ovarian cancer?

The most common early symptoms of ovarian cancer are:

  • Bloating
  • Pelvic or abdominal pain
  • Trouble eating or feeling full quickly
  • Frequent or urgent urination

Keep in mind that the symptoms above are fairly common, and it is necessary to talk with your doctor to determine a diagnosis.

What are the risk factors for ovarian cancer?

Risk factors for ovarian cancer incude:

  • Age
  • Obesity
  • Reproductive history
  • Birth control
  • Gynecologic surgery
  • Fertility drugs
  • Androgens (male hormones) or drugs that increase androgens
  • Estrogen therapy and hormone therapy
  • Family history of ovarian cancer, breast cancer, or colorectal cancer
  • Personal history of breast cancer
  • Talcum powder
  • Diet
  • Analgesics (including aspirin and acetaminophen medicines)
  • Smoking and alcohol use
How can I take steps to decrease my risk for ovarian cancer?

Most women have one or more risk factors for ovarian cancer. Risk factors include:

  • Age; about two-thirds of women with ovarian cancer are 55 or older.
  • A high-fat diet
  • Family history of ovarian cancer
  • Fertility drugs
  • Number of pregnancies; the greater the number of pregnancies, the lower the risk
  • Race: Caucasian women have the highest risk

However, most of the common factors only slightly increase risk. So far, knowledge about risk factors has not translated into practical ways to prevent most cases of ovarian cancer.

Some strategies that address ovarian cancer risk factors of are easily followed, and others require surgery. Women concerned about their risk of ovarian cancer should it with their doctor.

Analgesics. In some studies, both aspirin and acetaminophen have been shown to reduce the risk of ovarian cancer. However, the information is not consistent, and women should not take these medicines regularly to prevent ovarian cancer. More research is needed on this issue.

Diet. A number of studies have shown a reduced rate of ovarian cancer in women who ate a diet high in vegetables. The American Cancer Society recommends eating a variety of healthful foods, with an emphasis on plant sources. Even though the impact of these dietary recommendations on ovarian cancer risk remains uncertain, following these recommendations can help prevent several other diseases, including some other types of cancer.

Oral contraceptives. Using birth control pills decreases the risk of developing ovarian cancer, especially among women who use them for several years. Women who used oral contraceptives for three or more years have about a 30%to 50% lower risk of developing ovarian cancer compared to women who have never used oral contraceptives. Recent research suggests that contraceptives reduce risk in women who have mutations of the BRCA1 and BRCA2 genes. But this is not certain, as some studies have shown no decrease in risk.

Pregnancy and breast-feeding. Having one or more children, plus prolonged (one year or more) breast-feeding, also may decrease your risk. Doctors do not recommend making choices about when to have a child specifically for the purpose of reducing ovarian cancer risk, especially since using oral contraceptives will have a greater impact on this risk.

Tubal ligation or hysterectomy. Tubal ligation is a surgical procedure to "tie" the fallopian tubes to prevent pregnancy. When performed after childbearing, tubal ligation may reduce the chance of developing ovarian cancer by up to 67 percent. A hysterectomy may also reduce your risk. Tubal ligation has also been shown to be effective in reducing the risk of ovarian cancer in women who have the BRCA1 mutation. It is not certain if it will decrease the risk for women with the BRCA2 mutation.

No one knows for certain why tubal ligation and hysterectomy decrease the risk of ovarian cancer. One theory is that some cancer-causing substances may enter the body through the vagina and pass through the uterus and fallopian tubes to reach the ovaries. This may explain the effect on ovarian cancer risk of removing the uterus or blocking the fallopian tubes.

What kinds of tests are available to screen for ovarian cancer?

Regular women’s health exams. During a pelvic exam, the healthcare professional feels the ovaries and uterus for size, shape, and consistency. Although a pelvic exam is recommended because it can find some reproductive system cancers at an early stage, most early ovarian tumors are difficult or impossible for even the most skilled examiner to feel. Pelvic exams may, however, help to identify other cancers or gynecologic conditions. Women should discuss the need for these exams with their doctor. 

Although the Pap test is effective in detecting cervical cancer early, it is not an effective test for finding ovarian cancer. 

Report symptoms to a doctor. Early cancers of the ovaries tend to cause symptoms that are relatively vague. These symptoms include abdominal swelling (due to a mass or accumulation of fluid), unusual vaginal bleeding, pelvic pressure, back pain, leg pain, and digestive problems such as gas, bloating, indigestion, or long-term stomach pain. Most of these symptoms can also be caused by other less serious conditions. 

By the time ovarian cancer is considered as a possible cause of these symptoms, it may have already spread beyond the ovaries. Also, some types of ovarian cancer can rapidly spread to the surface of nearby organs. Still, prompt attention to symptoms can improve the odds of early diagnosis and successful treatment, so all symptoms of ovarian cancer should be immediately reported to a healthcare professional. 

Screening tests for ovarian cancer. Although there has been a lot of research to develop a screening test for ovarian cancer, there hasn’t been much success so far. But there are some tests that might help some women.

Women with a high risk of developing epithelial ovarian cancer, such as those with a very strong family history of this disease, may be screened with transvaginal sonography (an ultrasound test performed with a small instrument placed in the vagina) and blood tests. Transvaginal sonography is helpful in finding a mass in the ovary, but it does not accurately detect which masses are cancers and which are benign diseases of the ovary. 

Blood tests for ovarian cancer may include measuring the amount of CA-125 (also known as OC-125). The amount of this protein in the blood is higher in many women with ovarian cancer. However, some non-cancerous diseases of the ovaries can also increase the blood levels of CA-125, and some ovarian cancers may not produce enough CA-125 to cause a positive test result. When these test results are positive, it may be necessary to do a transvaginal ultrasound test and take samples of fluid from the abdomen or tissue from the ovaries to find out if a cancer is really present. 

In early studies of women at average risk for ovarian cancer, these screening tests did not lower the number of deaths caused by ovarian cancer. For this reason, transvaginal sonography and the CA-125 blood test are not recommended for ovarian cancer screening of women without known strong risk factors. In women at high risk, these tests are often done, but it is not known how helpful they are. Ways to improve ovarian cancer screening tests are being researched. Hopefully, further improvements will make these tests effective enough to lower the ovarian cancer death rate.