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Because the symptoms of ovarian cancer are usually
subtle, the majority of cases are not detected until advanced stages, when the chances of
survival are generally low. However, in a promising new study, researchers from the U.S.
Food and Drug Administration and the National Cancer Institute have found that a test that
analyzes protein patterns in the blood may help detect ovarian cancer in early stages and
could eventually become an effective method of screening for the disease in high-risk
women as well as the general population.
The National Cancer Institute estimates that approximately one out of 57 women will
develop ovarian cancer during their lifetime. Ovarian cancer is the sixth most common
cancer among women and the fifth leading cause of cancer deaths in women. The American
Cancer Society estimates that 23,400 new cases of ovarian cancer were diagnosed in 2001,
and approximately 13,900 women died from ovarian cancer last year. While a variety of
methods are used to diagnose ovarian cancer, there is currently no reliable means of
screening for the disease.
In an effort to develop an effective screening tool for ovarian cancer, Dr. Emanuel F.
Petricoin, III, of the Food and Drug Administration and his colleagues analyzed blood
samples from 50 women with ovarian cancer and 66 women without ovarian cancer. Their
analysis involved a special technique called mass spectroscopy, which sorts proteins and
other molecules according to weight and electrical charge. According to the researchers,
the analysis can provide "snapshots" of thousands of proteins at the same time.
Dr. Petricoin and her colleagues were able to use the analysis to determine patterns of
proteins that were associated with ovarian cancer.
Specifically, the researchers were able to correctly identify all 50 ovarian cancer
cases in their study, including 18 cases of Stage I ovarian cancer—an early form of
the disease. Furthermore, the study only produced a 5% false positive rate (that is, the
test detected ovarian cancer in 3 of the 66 women who did not have the disease). The
researchers suggested that either the test was inaccurate in these cases or that these
women had ovarian cancer tumors that were too small to be diagnosed.
Nevertheless, the researchers believe the results of the new blood test are very
encouraging and could eventually lead to a new screening test for women at high risk for
the disease and the general population. The researchers also said that the test may
improve the accuracy of screening when combined with other methods, such as ovarian ultrasound. Clinical trials of the new blood test are
continuing at the National Cancer Institute.
The early detection of ovarian cancer greatly increases the chances that the disease
can be successfully treated. If patients are diagnosed with ovarian cancer before the
cancer has spread outside the ovary, they have a 95% chance of surviving five years or
longer. However, the American Cancer Society estimates that only 25% of ovarian cancer
cases are currently diagnosed in early stages.
Ultrasound, CT, and MRI are
all used to help detect and diagnose ovarian cancer. In addition, a blood test that
measures the level of a tumor protein called CA-125 may also be used to diagnose ovarian
cancer. However, this test is not always an accurate method of determining whether a woman
has ovarian cancer and is usually performed in conjunction with other tests.
The symptoms of ovarian cancer are typically subtle and may not appear until the
disease has progressed to advanced stages. However, all women should be aware of the
symptoms and report any persistent symptom to their physician for clinical examination.
Women with a family or personal history of ovarian cancer should be particularly aware of
disease symptoms and have regular physician exams.
Ovarian cancer symptoms include:
- Pelvic or abdominal pain, pressure, swelling, or discomfort
- Vague, but persistent, gastrointestinal upsets such as gas, nausea, and indigestion
- Frequency and/or urgency of urination in the absence of an infection
- Unexplained changes in bowel habits
- Unexplained weight gain or weight loss, particularly weight gain in the abdominal region
- Pelvic and/or abdominal swelling, bloating, and/or feeling of fullness
- Pain during intercourse
- Ongoing fatigue
- Leg pain
- Unusual vaginal bleeding—a rare sign of ovarian cancer. More likely, vaginal
bleeding is a sign of another type of abnormality. Bleeding may occur between menstrual
periods. Heavier than normal menstrual bleeding, and menstrual bleeding that lasts longer
than normal are considered unusual signs.
Further clinical trials of the new ovarian cancer blood test will determine whether it
is effective and may be used on high-risk women or the general population.
Additional Resources and References
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