Jan. 28, 2010 -- When symptoms such as nausea, bloating, or pelvic or abdominal pain suggest ovarian cancer, evaluation results in a diagnosis of ovarian cancer in about 1% of the time, according to a new study.
''This [study] put a number on understanding how many women with [these] symptoms are really likely to have ovarian cancer," says study researcher Mary Anne Rossing, PhD, of the Fred Hutchinson Cancer Research Center in Seattle. The study is published online in the Journal of the National Cancer Institute.
''Among women who have symptoms suggestive of ovarian cancer, the number who actually has ovarian cancer is one in 100," Rossing says. "The number who has early stage is even lower."
Even so, Rossing and other experts say the new findings don't refute earlier research that suggested ovarian cancer is no longer a "silent killer." A 2009 British study linked seven key symptoms to ovarian cancer.
''Symptoms exist, we should pay attention to them, but they are not a diagnostic or screening test, and they are not specific," says Beth Karlan, MD, director of the Women's Cancer Research Institute at the Samuel Oschin Comprehensive Cancer Institute at Cedars-Sinai Medical Center in Los Angeles, who co-wrote an editorial published with the study. Symptoms that could point to ovarian cancer are sometimes vague and could also point to a host of other medical problems.
Rossing and colleagues interviewed 812 women, ages 35 to 74, who had been diagnosed with ovarian cancer from January 2002 through December 2005. They also interviewed 1,313 women from the general population without a diagnosis of the cancer.
Women reported whether they had any of the symptoms associated with ovarian cancer (nausea, diarrhea, or constipation, pelvic or abdominal pain, bloating or feeling full, urinary frequency or urgency), how long they had had them, and how often.
Then the researchers evaluated whether each woman's ''symptom index" was positive. It was positive if pelvic or abdominal pain or bloating or feeling full was reported at least daily for a week or more, with an onset of less than 12 months before the diagnosis (or before a specific reference date for the healthy women).
Predicting Ovarian Cancer
In most women diagnosed with ovarian cancer, the symptoms surfaced about five months or less before the diagnosis. Those diagnosed with early-stage cancers were more likely to report nausea than those diagnosed with late-stage cancers.
Then they computed the chance that a woman with a specific symptom has the cancer. Overall, it ranged from 0.6% to 1.1%. But it was less than 0.5% for the early-stage cancers.
Rossing's team concludes that 100 women with symptoms suggestive of ovarian cancer need to be evaluated to detect one with ovarian cancer.
"This [study] again tell us there are symptoms, but don't rely on them to make a diagnosis," says Karlan. The findings do point to a need, she tells WebMD, to develop a true screening test for ovarian cancer.
In recent years, women have become more aware of symptoms suggestive of ovarian cancer and the need to be checked out, Karlan and others say. That's largely due to a consensus statement issued in 2007 by the American Cancer Society and others, noting that certain symptoms (such as bloating, pelvic pain, or abdominal pain) are more likely to be present in women with ovarian cancer.
''I think this study says symptoms occur in ovarian cancer even in early stages," Karlan says. But, she adds, "it makes the point that even the symptoms themselves are not necessarily going to lead to diagnosing it at an earlier stage."
The take-home message, Karlan says, is that when women have these symptoms, they need to discuss them with their doctor and decide what type of medical testing should be done. Among tests that can be ordered are CT scans, MRIs, and ultrasound.
Karen Orloff Kaplan, CEO of the advocacy group the Ovarian Cancer National Alliance, says she doesn't find the study results discouraging. "What it is saying is, ovarian cancer is a rather rare occurrence," she tells WebMD. "If you [have] 100 women [with symptoms suggestive of the cancer], only one will have it. It's not saying the other 99 were missed."
She says the study findings also point to the need for women to pay attention to symptoms suggestive of ovarian cancer while bearing in mind that the symptoms will likely not lead to a diagnosis of ovarian cancer.
About 21,550 women in the U.S. were expected to learn they have ovarian cancer in 2009, according to the American Cancer Society, and about 14,600 were expected to die from it.