Ovarian Cancer
The Silent Killer
The ovaries are almond-sized reproductive organs located in the pelvis, one on either side of the uterus. The ovaries produce eggs (ova) one of which migrates each month through the connecting fallopian tubes to the uterus in preparation for fertilization. The ovaries also produce the hormones, estrogen and progesterone.
Cancer that begins in the cells of the ovaries is called ovarian cancer and includes epithelial cell cancer (the most common type), germ cell cancer and stromal cancer, depending on the cell of origin.
Ovarian cancer is the fifth leading cause of cancer death in North American women. About 23,000 North American women develop ovarian cancer every year and about 15,000 die from the disease 1.
A woman’s chances of surviving ovarian cancer are excellent if her disease is diagnosed early -- that is, before malignant cells have spread from the ovaries to other organs. In the earliest stages of ovarian cancer, five-year survival is about 94%1 But only about 19% of women are diagnosed in the earliest stages.1
Symptoms
Ovarian cancer is known as the "silent killer." In early stages most women with this cancer do not show any symptoms or signs of disease. Thus, most ovarian cancer is not diagnosed until it is advanced.
Even in later stages of disease, the symptoms of ovarian cancer mimic symptoms of many other illnesses that are not cancer, such as gastrointestinal diseases. Such symptoms include abdominal pressure, swelling or bloating, urinary urgency, pelvic discomfort and pain. Other non-specific problems that may be experienced by women with ovarian cancer include indigestion, gas, nausea, low back pain, abnormal bleeding, pain during intercourse, diarrhea or constipation, unexplained weight gain or loss and lack of energy.2 Some of these symptoms may be viewed as merely inconvenient and so visits to the physician for diagnosis may be delayed, a very dangerous thing considering how fatal ovarian cancer is and how curable it is if caught early.
Risk Factors for Ovarian Cancer
Research continues into the causes of ovarian cancer. Researchers have identified risk factors that may increase the chances of developing ovarian cancer.1-3) However, 95% of ovarian cancers occur in women with no risk factors.
The best established risk factors include:
- Age older than menopause (though younger women can develop ovarian cancer, most cases occur in women over age 50).
- Family history – having a first degree relative such as a mother, daughter or sister develop ovarian cancer, especially early onset cancer, is a risk factor.
- Personal history of breast cancer or familial history of breast or colon cancer may increase risk.
- Carrying mutation(s) in the BRCA-1 or BRCA-2 genes has also been associated with a significantly increased risk of ovarian cancer.
- Reproductive factors: Early onset of menstruation, late menopause over age fifty, having no children or having a first child after age thirty may be risk factors for ovarian cancer.
- Fertility drugs or hormone replacement therapy may contribute to risk.
- Taking oral contraception (birth control pills) appears to decrease risk of ovarian cancer.
Screening for Ovarian Cancer
There is no screening test for ovarian cancer that has been found in studies to reduce the risk of death from this type of cancer in the general population. Health authorities do not recommend screening with tests currently available, which have high false positive rates that can lead to unnecessary worry, expense and treatments, such as surgery.1-4On the other hand, some women at high risk with a strong family history of ovarian cancer or genetic factors may be advised by their physicians to be screened regularly for ovarian cancer. Screening tests for women at high risk include pelvic examinations, pelvic ultrasound testing or blood tests for the protein, CA-125, that may be elevated in women with ovarian cancer .1-4 These tests, however, may lead to a false sense of security. These tests lack high sensitivity and so many women at high risk for developing ovarian cancer may fail to be diagnosed.
References and Further Information
- American Cancer Society. Detailed Guide. Ovarian Cancer. [ link ]
- MayoClinic.com. Ovarian Cancer. [ link ]
- Bhoola S and Hoskins WJ. Diagnosis and management of epithelial ovarian cancer. Obstetrics and Gynecology. 2006; 107: 1399-1410.
- US National Institutes of Health. National Cancer Institute. Ovarian cancer. [ link ]