What is Ovarian Cancer?
Most cancers are named after the part of the body where the cancer originates. Ovarian cancer starts in a woman's ovaries. There are two ovaries, one on each side of the pelvis. The ovaries produce eggs and are the main source of the female hormones estrogen and progesterone.

There are many types of tumors that can start in the ovaries. Some are benign or non-cancerous, and the patient can be treated by surgically removing the ovary or the part of the ovary containing the tumor. Some are malignant or cancerous. The treatment options and the outcome for the patient depend on the type of ovarian cancer and how far it has spread before it is diagnosed.

There are three main types of ovarian tumors. They are named for the kind of cells that they start from. Epithelial tumors, which develop from the cells that cover the outer surface of the ovary, account for 85 to 90 percent of all cancers of the ovaries. The second type of tumor starts in the germ cells that form the eggs in the ovary. The third type of tumor starts from the stromal cell tissue, which holds the ovary together and produces the female hormones.

Difficult to detect in its early stages, ovarian cancer is often permitted to progress to an advanced stage before it is detected. In fact, the majority of women, 77 percent, are diagnosed after the disease has reached an advanced stage. Despite advancements in surgery and chemotherapy treatments, the overall five-year survival rate for women with advanced stage ovarian cancer has remained constant over the past 30 years at approximately 15 percent.

Conversely, those women diagnosed with early stage (Stage I) disease have an overall five-year survival rate approaching 90-95 percent. Clearly, early-stage detection of ovarian cancer is the best way to improve survival.

Please consult our fact sheet and ovarian cancer statistics page for additional information.