The Push for Early Detection of Ovarian Cancer
Research offers hope in the fight against this often-fatal disease
SUNDAY, March 10, 2002 (HealthDayNews) -- Of all the cancers that can strike a woman, ovarian cancer isn't that common. Yet, it's among the most deadly.
The reason: Like all cancers, the earlier ovarian cancer is detected, the easier it is to treat and the higher the survival rate. However, ovarian cancer is tough to spot in the beginning. Often, women have minor symptoms -- or no symptoms at all -- until the cancer has reached an advanced stage.
Several recent discoveries, however, have given researchers hope that a breakthrough in detection will come in the near future.
"Given modern methodology, there is a good chance that we will find something sooner rather than later for early detection of ovarian cancer," says Dr. Eddie Reed, an ovarian cancer specialist and former National Cancer Institute researcher. "The news should be hopeful."
Actually, it already is.
Researchers have designed a computer program that looks for distinctive patterns of proteins in blood; it appears to be a promising new screening tool for early detection of ovarian cancer.
In its first test, the computer analysis of "proteomic patterns" was 100 percent accurate in detecting ovarian cancer and 95 percent accurate in determining that women with other diseases did not have cancer of the ovaries, according to a recent report in The Lancet.
Such a test -- particularly a noninvasive one -- would be welcome, experts say. Researchers at the National Cancer Institute, the Food and Drug Administration and Correlogic Systems, Inc., a private company, developed the technique.
The results of the first test "are certainly good enough to justify further evaluation," says Dr. David A. Fishman, director of the National Ovarian Early Detection Program at Northwestern University, a study participant.
There are other promising developments.
Epidemiologist Sara H. Olson's recent study found that women with ovarian cancer do experience certain, though subtle, symptoms. Being aware of those symptoms could lead to earlier detection of the disease, she explains.
In her study, Olson examined 419 women, aged 40 to 70. Forty percent of them had ovarian cancer -- some early-stage, some late-stage -- and 60 percent were cancer-free.
She found that 71 percent of the women with cancer reported constant feelings of bloating in the abdomen, compared to only 9 percent of those without the disease. In addition, 52 percent of women with the cancer reported abdominal or lower back pain, while only 15 percent of the control group did. Finally, nearly half the women with the cancer said they lacked energy, while only 16 percent of the healthy women reported fatigue.
"If women are better educated [about these symptoms], they could think about going to the doctor," says Olson, a staff member at Memorial Sloan-Kettering Cancer Center in New York City. Her study appeared in a recent issue of the journal American College of Obstetricians and Gynecologists.
Unlike other female cancers, such as those of the breast and cervix, there is no definitive way yet to detect ovarian cancer in its early stages. So, although ovarian cancer isn't that common -- it ranks fifth in incidence among cancers affecting women, with approximately 23,000 new cases each year -- it causes 14,000 deaths annually. By comparison, there are 190,000 new cases of breast cancer each year -- and 40,000 deaths, according to the American Cancer Society.
Currently, there are two tools available for detection of ovarian cancer, but neither is effective at early detection, doctors say. The first, a transvaginal ultrasound, can spot suspicious abnormalities in the ovaries. The second is a blood test for a protein -- called CA 125 -- that is present in higher-than-normal levels in ovarian tumors.
However, the ultrasound isn't considered reliable for early screening because it's often unable to detect new tumors. The CA 125 test also isn't dependable because it isn't known how early in the development of a tumor the protein levels rise, experts say.
However, effective tools for the diagnosis of early-stage ovarian cancer could be available in just a few years, cancer experts say.
One of the most promising was detailed in a recent issue of the Journal of the National Cancer Institute. Doctors at Boston's Brigham and Women's Hospital have found the enzyme prostasin is present in significantly higher levels in both early-stage and late-stage ovarian tumors.
While more research is needed, the hope is a simple test will soon be available to detect the higher-than-normal prostasin levels in early-stage cancer victims.
"We only had 200 samples, and need to screen 1,000 women for more accurate information, but it's hopeful," says Samuel Mok, director of the gynecologic oncology laboratory at Brigham and Women's and lead author of the report.
It was in the Brigham lab that the CA 125 test was devised.
Mok says that since the discovery of prostasin, he and his colleagues have found two other proteins that could be possible "markers," or warning flags, for early-stage ovarian cancer.
"I don't believe that one marker is enough. We need more tests for specificity. But the CA 125 test, in combination with tests for several markers, could detect [ovarian cancer] in the early stages," he says.
Such tests might be available within in two to five years, Mok estimates.
What To Do: For a detailed explanation of ovarian cancer, including risk factors, symptoms and treatments, visit the National Cancer Institute. Also on the NCI site is information about research into early detection of cancer.