Cancer of the female ovary is the second-most-common gynecologic malignancy, with 26,800 new cases and 14,200 deaths estimated
for 1997. In the United States it is the number-one cause of death from gynecological cancer and the fifth-leading cause of death from all cancers in women. The average age at diagnosis is 63 years. Early symptoms of ovarian cancer resemble many different illnesses and may
include vague gastrointestinal complaints, such as nausea, indigestion, a feeling of fullness before a meal is completed, and constipation. At diagnosis the most common signs and symptoms are abdominal discomfort or pain and abdominal swelling, which are related to the presence of large masses and accumulation of fluid in the lower abdomen.
The most common type of ovarian cancer is epithelial, accounting for
approximately 90% of all ovarian cancers. Epithelial ovarian cancers appear to arise from the surface of the ovary and spread by shedding cancer cells, which are then implanted throughout the lower abdomen. The disease usually spreads without notable symptoms, accounting for the fact that over 70% of epithelial ovarian cancers are diagnosed after the tumor has already spread beyond the ovaries. The other types of ovarian cancer are germ cell and sex cordÐstromal tumors.
The cause of ovarian cancer is poorly understood. Epidemiologic studies have shown that risk factors for developing this cancer include increased age, never giving birth, infertility, a history of breast cancer or endometrial cancer, and a family history of ovarian cancer. Women who have had one or more full-term pregnancies, used oral contraceptives, or breast-fed their babies are less likely to develop ovarian cancer. Approximately 10% of ovarian cancers appear to be genetic. The BRCA1 and BRCA2 genes, associated with breast cancer, may also be related to the development of ovarian cancer.
There is no reliable screening method for ovarian cancer, but a number of techniques are under study, including pelvic ultrasound, and measurement of serum tumor markers such as CA 125, which has been found to be elevated in approximately 80% of women diagnosed with ovarian cancer. Women with a strong family history of breast or ovarian cancer, or other risk factors, are the major focus of screening studies. For some women with a strong family history of ovarian cancer or the presence of a BRCA1 or BRCA2 mutation, preventive removal of the ovaries may be recommended.
Treatment for ovarian cancer consists of primary surgery to definitively diagnose the condition and to remove the tumor mass or masses. If the tumor appears to be confined to the ovary, the surrounding abdominal cavity surfaces, all organ surfaces, and the lymph nodes are thoroughly checked for cancer cells. If the tumor has spread extensively, as much of the mass as possible is removed. In addition to the amount of residual tumor at completion of primary surgery, major prognostic factors include amount of tumor left after surgery, extent of spread, and microscopic appearance. Treatment for most women with ovarian cancer, except those with certain low-grade or borderline tumors confined to the ovary, includes chemotherapy with a combination of drugs. Some patients may receive radiation treatment as well. If there is no evidence of cancer at completion of chemotherapy, standard options for further management include regular surveillance or, in many cases, second-look surgery to assess disease status. For women who develop recurrent cancer, treatment options include conventional chemotherapy, bone-marrow transplant, hormonal agents such as tamoxifen, or experimental treatments such as gene therapy.
The overall five-year survival rate for all women with ovarian cancer is approximately 40%. For women with tumors confined to the ovary, the 5Ðyear survival rate may be as high as 90%, but for women with advanced tumors, the five-year survival rate drops to 15Ð20%.