Overview of Ovarian Cancer
Ovarian cancer is a disease produced by the rapid growth and division of cells within one or both ovariesreproductive glands in which the ova, or eggs, and the female sex hormones are made. The ovaries contain cells that, under normal circumstances, reproduce to maintain tissue health. When growth control is lost and cells divide too much and too fast, a cellular mass or tumor is formed. If the tumor is confined to a few cell layers, for example, surface cells, and it does not invade surrounding tissues or organs, it is considered benign.
If the tumor spreads to surrounding tissues or organs, it is considered malignant, or cancerous. When cancerous cells break away from the original tumor, travel through the blood or lymphatic vessels, and grow within other parts of the body, the process is known as metastasis.
Click on the image for enlargement.
Many kinds of tumors can form in the ovaries. In fact, there are over 30 known histopathologic, or diseased tissue, types (see also Types of Ovarian Cancer). Experts group ovarian cancers within three major categories, according to the type of cells from which they were formed.
- Epithelial cancers, which are the most common ovarian cancers, arise from cells lining or covering the ovaries.
- Germ cell cancers start from germ cells (cells that are destined to form eggs) within the ovaries.
- Sex cord, stromal cell cancers, begin in the cells that hold the ovaries together and produce female hormones.
Incidence and Prevalence of Ovarian Cancer
Ovarian cancer is a disease that principally affects middle and upper-class women in industrialized nations. It is uncommon in underdeveloped countries, perhaps because of different dietary factors in these regions (see also Causes of Ovarian Cancer). Among American women, ovarian cancer is the fifth most common cancer, and it is the leading cause of death from all types of gynecologic cancer.
It is estimated that approximately 30,000 new cases of ovarian cancer will be diagnosed this year, with 15,000 women dying from this disease. Nearly 2% of women born in the United States are at risk of developing ovarian cancer in their lifetimes. Ovarian cancer most frequently appears in women who are older than 60 (about 50 percent of patients are over age 65), although it may occur in younger women who have a family history of the disease. Ovarian cancer is responsible for 5% of all cancer deaths among women.
There are marked differences in survival among patients with ovarian cancer, depending on factors such as age, cancer stage, and tissue type. Younger patients tend to fare better in all stages than do older patients, whereas race does not play a factor, as it does in other cancers. Survival rates are similar in black and white women.