Ovarian cancer is fairly uncommon, yet it is the 5th leading cause of cancer death in women and the leading cause of death from gynecologic malignancies. The cause is unknown. The disease is more common in industrialized nations, with the exception of Japan. In the United States, females have a 1.4 to 2.5% (1 out of 40-60 women) lifelong chance of developing ovarian cancer.
Older women are at highest risk. More than half of the deaths from ovarian cancer occur in women between 55 and 74 years of age and approximately one quarter of ovarian cancer deaths occur in women between 35 and 54 years of age.
Ovarian cancer is disproportionately deadly for a number of reasons. First, symptoms are vague and non-specific, so women and their physicians frequently attribute them to more common conditions. By the time the cancer is diagnosed, the tumor has often spread beyond the ovaries.
Also, ovarian cancers shed malignant cells that frequently implant on the uterus, bladder, bowel, and lining of the bowel wall (omentum). These cells can begin forming new tumor growths before cancer is even suspected.
Second, because no cost-effective screening test for ovarian cancer exists, more than 50 percent of women with ovarian cancer are diagnosed in the advanced stages of the disease.
The risk for developing ovarian cancer appears to be affected by several factors. The more children a woman has, the lower her risk of ovarian cancer. Early age at first pregnancy and the use of some oral contraceptive pills have also been shown to have a protective effect. In contrast, the use of fertility drugs may be associated with an increased chance of developing this cancer, although there is ongoing controversy over this.
Certain genes may also increase risk, including BRCA1 and BRCA2, which also increase breast cancer risk and the chances that a woman will be affected by either cancer at a younger age. Patients with a personal history of breast cancer, or a family history of breast and/or ovarian cancer, may have an elevated risk. A strong family history of uterine, colon, or other gastrointestinal cancers may indicate the presence of a syndrome known as hereditary non-polyposis colon cancer (HNPCC), which confers a higher risk for developing ovarian cancer.
Other factors that have been investigated, such as talc use, asbestos exposure, high dietary fat content, and childhood mumps infection, are controversial and have not been definitively proven.
