Ovarian Cancer

I

Introduction

Ovarian Cancer, cancerous tumor that develops in the ovaries, two almond-size glands on either side of a woman’s uterus. The ovaries produce eggs and release hormones that help regulate menstruation and pregnancy. The American Cancer Society estimates that about 22,000 new cases of ovarian cancer are diagnosed annually in the United States, and an estimated 15,000 women die from the disease each year. In Canada, about 2,500 cases of ovarian cancer are diagnosed and about 1,700 women die from the disease each year. Ovarian cancer is the deadliest cancer of the female reproductive system.

II

Tumors and Cysts

When the body’s process of cell renewal and cell death goes awry, excess cells can create a mass of tissue called a tumor. About 80 percent of tumors on the ovaries are benign (noncancerous). Cells from benign tumors do not spread to nearby tissues or to other parts of the body. Once removed, they rarely recur. Another kind of benign growth is a fluid-filled sac called a cyst. Many women, even in their 20s, develop ovarian cysts. Cysts sometimes disappear without treatment; in other cases, they must be removed surgically.

Malignant tumors are cancerous and more serious than benign tumors. They can spread to other tissues through the circulatory system in a process called metastasis. Ovarian tumors also can shed cells that grow into new tumors. Although ovarian cancer may metastasize anywhere in the body, it commonly spreads to nearby organs such as the stomach and intestines.

III

Risk Factors for Ovarian Cancer

Although a woman’s likelihood of developing ovarian cancer is small, certain factors increase her chances of developing the disease. Women with a close female relative (a mother, sister, or daughter) who has ovarian cancer have an increased risk of developing the disease. Having two close relatives with the disease increases the risk even more. A woman who has a mutated version of a gene called BRCA1 or a gene called BRCA2 has a significantly increased risk for developing ovarian cancer or breast cancer. A woman who has had cancer of the breast, uterus, or colon also has a higher risk for ovarian cancer. The risk for ovarian cancer increases with age: Most cases occur in women over age 55.

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Giving birth appears to reduce a woman’s chances of developing ovarian cancer, possibly because pregnancy reduces the number of times a woman ovulates (releases an egg). Women who have never been pregnant have a higher risk than women who have had a child. Having several pregnancies seems to further lower a woman’s risk for the disease.

IV

Symptoms and Diagnosis

Physicians long believed that ovarian cancer seldom produces symptoms until it begins to spread. However, cancer researchers have recently identified a group of warning signs that may point to ovarian cancer in its early stages. These symptoms include persistent bloating, swelling, or pain in the abdomen, difficulty eating or feeling full quickly, urgent or frequent urination, and vaginal bleeding not associated with menstruation. Many of these symptoms have other causes and in most cases do not indicate the presence of ovarian cancer. Irritable bowel syndrome, for example, is a far more common cause of most of these symptoms. Several cancer organizations advise women to see their gynecologist if these symptoms develop suddenly and occur daily over two to three weeks.

If a physician suspects an ovarian tumor, ultrasound may be used to create a picture of the organ from a pattern of sound-wave echoes. Tumors produce different echoes than healthy tissue does. In addition, a blood sample may be tested in a laboratory for the presence of CA-125, a tumor marker (biochemical substance) that is sometimes produced by ovarian cancer cells. Because CA-125 may also be present in women who have benign ovarian conditions, this test does not provide a definitive diagnosis. Final diagnosis of ovarian cancer depends on a biopsy, in which a sample of tumor tissue is removed during a surgical procedure and then examined under a microscope. If cancerous cells are detected in the tumor, the physician may order additional tests to find out if the cancer has spread to other organs.

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