London - A new blood test could detect ovarian cancer two years before women are currently diagnosed.
It could save thousands of lives, and will strengthen calls for women to be invited for screening for ovarian cancer as well as for breast cancer.
The blood test looks for four proteins released into the bloodstream by the most common type of ovarian cancer.
British scientists carried out a trial of the test using 80 initially healthy women from a previous study, whose blood was taken every year, and of whom 49 were later diagnosed with epithelial ovarian cancer.
A year ahead of their diagnosis, the test was able to identify 68 percent of those who would develop aggressive ovarian cancer and 53 percent of those who would get a more slow-growing cancer.
Two years before the women were diagnosed, scientists detected 28 percent of those who would get aggressive cancer and 20 percent of those set to get the less aggressive kind.
A test that is able to detect ovarian cancer one or two years earlier could mean the difference between life and death because by the time most women visit the doctor with confusing symptoms such as bloating and stomach pain, the cancer has already spread.
If it is diagnosed at the earliest stage, 92 percent of women with ovarian cancer survive five years or more, but among those diagnosed with the most advanced cancer, this falls to 12 percent.
Two-thirds of women with ovarian cancer are diagnosed once the disease has already spread. Study leader Dr Robert Graham, from Queen’s University Belfast, said: "Most ovarian cancer cases are caught at a late stage, so we hope to have developed a test which could detect ovarian cancer earlier. We hope, with further research, we can build the case to push experts towards a national screening programme for ovarian cancer."
If a GP suspects ovarian cancer, an abdominal examination can be followed by a blood test for a protein called CA125, which may then lead to an ultrasound scan.
But the researchers, whose study is published in the British Journal of Cancer, say the three newly discovered proteins, taken together, could improve the effectiveness of the test, because CA125 is also raised in other conditions such as endometriosis.
They now want to try their test on a larger group of women and all types of ovarian cancer.
Annwen Jones, chief executive of the charity Target Ovarian Cancer, said: "Progress is desperately needed in detecting ovarian cancer earlier. These are very promising early results, but the number of women involved is too small."