By Dennis Thompson
SUNDAY, Oct. 19 (HealthDay News) -- Ovarian cancer is one of the most difficult cancers to diagnose, making it one of the most lethal.
The ovaries aren't easily accessible for examination, unlike a woman's skin or breast or cervix. And the symptoms that accompany ovarian cancer are vague and can be confused with other less life-threatening conditions.
"A lot of women with ovarian cancer will retrospectively say, 'Yes, I had these symptoms,' but the symptoms are vague and can be associated with other illnesses," said Debbie Saslow, director of breast and gynecologic cancer for the American Cancer Society.
Because of its elusive nature, ovarian cancer often isn't caught in time to save the patient. Three of every four ovarian cancer cases are diagnosed at an advanced stage, after the malignancy has spread beyond the ovary, according to the U.S. National Cancer Institute.
Although the fight against the disease has been slow and at times frustrating, doctors believe they are finally making some headway toward saving more lives.
When ovarian cancer is found at an early stage -- about 20 percent of the time -- it proves crucial to the woman's chances. About 94 percent of patients who receive an early diagnosis live longer than five years, according to the American Cancer Society.
That compares to an overall 46 percent survival rate for all women with ovarian cancer -- a rate that has improved a poor 8 percent over the last 30 years. During that same period, leaps in research have made a host of other cancers much more survivable.
"That's what makes ovarian cancer such a miserable diagnosis, because it's diagnosed so late that the best treatment isn't likely to really work," said M. Robyn Andersen, an associate member of the Public Health Sciences Division at Fred Hutchinson Cancer Research Center in Seattle. "If we can increase the rate of early diagnosis, that's probably the most likely way we're going to change the survival rate for ovarian cancer."
Andersen recently led a study that boosted the level of early stage ovarian cancer detection by 20 percent by combining a blood test with a questionnaire of potential symptoms.
And in another development, researchers are working on therapeutic vaccines to fight ovarian and breast cancer.
Ovarian cancer is relatively rare. There are about 40 to 45 new cases for every 100,000 women, Andersen said. A woman has a one in 72 chance of developing ovarian cancer in her lifetime, and a one in 95 chance of dying from it. The disease typically strikes older women, with about two-thirds of cases diagnosed in women 55 or older.
There are some symptoms that have been linked to ovarian cancer. They include pelvic or abdominal pain, bloating or increased abdominal size, difficulty eating or feeling full quickly, or more frequent urination or a recurrent urgent need to urinate.
Unfortunately, those symptoms are shared with a number of common ailments like irritable bowel syndrome, Saslow noted. "If a woman has had these symptoms for years, it's probably not ovarian cancer," she said. "It's probably something else."
Andersen's research found that a questionnaire in which a woman checks off these sort of symptoms ended up uncovering early stage ovarian cancer about 60 percent of the time in a group of high-risk women. And a blood test commonly used to track the health of women with ovarian cancer was able to detect early stage disease about 60 percent of the time, the research found.
But when the two tests were combined, they were able to identify 80 percent of early stage ovarian cancers in the group of women.
"That's very exciting, because that suggests the combination can detect women who need further diagnostic testing quickly," Andersen said.
Diagnostic tools ranging from ultrasound and X-rays to biopsy and blood tests can help confirm or reject a positive reading for early stage cancer.
While the research is promising, Saslow said the testing being explored by Andersen still isn't accurate enough to provide a true picture for women. Cancer is too often detected in healthy women, causing them unnecessary worry and pain.
"The problem, as the authors point out in that paper, is that in order to detect a good percentage of ovarian cancer, you also get a lot of false-positives," Saslow said. "You can either find a lot more cancers and have a lot more false-positives, or limit the number of false-positives but also limit the cancers you find."