It’s the fifth most common cancer among women: In the U.K., around 7,100 women a year are diagnosed with ovarian cancer. Due to the fact that early ovarian cancer often does not present any obvious or specific symptoms, when it is discovered it is commonly already at an advanced stage, making it more difficult to treat. But that could be about to change, as the results from a recent trial—the largest in the world for ovarian cancer screening—has just released some very encouraging early results.
As described in the Journal of Clinical Oncology, scientists discovered that regular blood tests for a particular protein, called CA125, could result in the detection of twice as many cases of ovarian cancers as conventional tests. By observing changes in the level of this protein over time, a team led by University College London was able to use statistical analysis to determine a more accurate prediction of a woman’s risk of developing the cancer.
“Ovarian cancer is particularly hard to spot at an early stage so it's vital that we find ways to diagnose the cancer sooner,” said Dr. James Brenton from Cancer Research UK. “A blood test to find women at risk of ovarian cancer is an exciting prospect, but this work still needs to be tested in women to see if it can save lives.”
This new method was able to detect cancer in 86% of women with ovarian cancer, double the number detected by normal techniques. The 14-year trial recruited over 200,000 postmenopausal women aged 50 and over, who were then randomly assigned different screening techniques. Of these, 46,000 of the women continued to have their blood tested once a year for CA125 levels after an initial standard test.
Despite the fact that ovarian tumors have been known to emit the protein for a while, traditionally CA125 has been seen as a highly inaccurate method to detect the cancer. This is because scientists used a fixed threshold of CA125 in the blood to identify those at risk. But not everyone is the same: Some women have much higher levels of the protein and don’t have the cancer, and others have much lower levels but do.
“CA125 as a biological marker for ovarian cancer has been called into question… What's normal for one woman may not be so for another. It is the change in levels of this protein that's important,” explained professor Ian Jacobs from the University of New South Wales, Australia, trial leader and co-inventor of the statistical approach used in the study.
Armed with this knowledge, the scientists developed a new statistical technique that took into account factors such as a woman’s age, the starting level of the protein, and how that changed over time. This enabled the team to vastly increase the ability of CA125 to predict the risk that a woman will have the cancer.
But the researchers involved in the trial warn that whilst these results are promising, it is still unknown whether more lives will be saved by this increase in detection. However, we should know more about this by the end of the year, when the results on the impact that the regular screening had on ovarian cancer deaths should be released. If the findings are positive, then Patrick Maxwell from the Medical Research Council is hopeful that “these exciting initial results could eventually go on to form the basis of a national screening programme for ovarian cancer.”
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