A new test may be able to detect ovarian cancer earlier than existing diagnostic tools.
Epithelial ovarian cancer, which makes up 90 per cent of ovarian cancer cases, is one of the deadliest types of cancer, with only 30 per cent of those with the disease living for more than five years after diagnosis.
One of the reasons for this is that epithelial ovarian cancer is asymptomatic for much of its course, so by the time people seek medical attention, it has reached advanced stages.
A blood test for a protein called CA125 is used to diagnose ovarian cancer, but it doesn’t always detect the disease reliably. A population screening programme trialled in more than 200,000 women in the UK failed to significantly reduce the number of deaths from ovarian cancer.
To develop a better test, Pan Wang at Peking University in China and his colleagues collected uterine fluid from 219 women with cancer, including those with early-stage ovarian cancer, late-stage ovarian cancer, benign ovarian cancer and endometrial cancer. The uterine fluid contains cells and metabolic products, or metabolites, that come from the ovaries and fallopian tubes.
Using chemical analysers called mass spectrometers, the researchers examined the fluid of 96 women to look for metabolites whose levels were markedly distinct for those with early-stage ovarian cancer. They identified a group of seven metabolites, including the amino acids tyrosine and phenylalanine, that could be used for diagnosis.
Next, they tested the fluids from the remaining 123 women for these seven metabolites and carried out the CA125 test on them. The new test accurately identified most of those with early-stage ovarian cancer and performed much better than the CA125 test in diagnosing ovarian cancer at an earlier stage.
The results are promising, but the test needs to be validated in a larger group of people, says Eric Eisenhauer at Massachusetts General Hospital in Boston. “Effective non-surgical testing for early-stage ovarian cancer has been elusive for more than five decades,” he says. “Most currently available tests for early detection have difficulty identifying ovarian cancer while it is still at an early stage. I would like to see this profile validated in a larger prospective data set, but this initial report shows much promise.”
Sujata Sharma at the All India Institute of Medical Sciences in New Delhi points out that the study didn’t include people without cancer as a comparison, and there may be other conditions that change the profile of metabolites in similar ways.