Can symptoms predict ovarian cancer?

28th January 2010 — When symptoms such as nausea, bloating or pelvic or abdominal pain suggest ovarian cancer, evaluation results in a diagnosis of ovarian cancer 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, of the Fred Hutchinson Cancer Research Centre in Seattle in the US. 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," Professor Rossing says. "The number who has early stage is even lower."

Two UK cancer charities have responded to the study, saying it would put women off seeing their GP if they suffer symptoms and are concerned.

Symptom index

Professor 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 study by researchers in Bristol 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 Dr Beth Karlan who co-wrote an editorial published with the new study. Symptoms that could point to ovarian cancer are sometimes vague and could also point to a host of other medical problems.

Professor Rossing and colleagues interviewed 812 women, ages 35 to 74, who had been diagnosed with ovarian cancer from January 2002 to 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, diarrhoea, 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 calculated the chance that a woman with a specific symptom has the cancer. Overall, it ranged from 0.6% to 1.1%. However, it was less than 0.5% for the early-stage cancers.
Professor 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 Dr Karlan. The findings do point to a need, she tells us, to develop a true screening test for ovarian cancer.