Yale researchers have developed a blood biomarker test with the ability to detect ovarian cancer in its early stages.
There is currently no screening test for ovarian cancer. Over 70 per cent of cases of ovarian cancer are detected at an advanced stage where the cancer has spread and is difficult to treat successfully. Ovarian cancer is difficult to diagnose in its early stages because the symptoms are vague, often associated with a number of benign conditions and may not present during the early stages of the disease.
A combination of tests is currently used to diagnose ovarian cancer including physical examination, an ultrasound or CT scan and a CA125 test. CA125 is a protein found in the blood. It is known as a tumour or cancer marker as increased levels may indicate that ovarian cancer is present. However, a CA125 test is not appropriate to use as a stand-alone test for ovarian cancer as there are a number of other causes for raised CA125 levels such as ovulation, menstruation, endometriosis, fibroids or benign ovarian cysts.
Researchers at Yale University have published the results of a phase II clinical trial looking for specific proteins in the blood to indicate the presence of ovarian cancer.
The trial involved 500 participants and is based on the analysis of six protein biomarkers. The researchers tested for both the proteins the tumour itself produces and the proteins produced by the body in response to the presence of the tumour. Testing for this combination of biomarkers allowed the researchers to detect ovarian cancer in its early stages.
The Yale test has a sensitivity** of 91.6 per cent for stage I and II ovarian cancer. By comparison, the CA125 test has a sensitivity of less than 60 per cent in the early stages of the disease. Overall, for all stages of the disease (I – IV), the Yale test has a sensitivity of 95.3 per cent and a specificity* of 99.4 per cent.
The researchers have now begun a phase III trial involving 2000 participants to further evaluate the test.
** Sensitivity refers to the test’s accuracy in being ‘positive’ if the woman does have ovarian cancer. Specificity refers to the test’s accuracy in being ‘negative’ if the woman does not have ovarian cancer.
National Breast and Ovarian Cancer Centre* comment
Given the high mortality from ovarian cancer, new research into ways of increasing the accuracy of diagnosis and the early detection of ovarian cancer is to be fostered.
The Yale test is one of a number of tests currently in development to detect ovarian cancer in its early stages through the presence of protein biomarkers in the blood. With further validation in clinical trials, these tests may have a role in the diagnosis of ovarian cancer and the screening of women who are at high risk of the disease.
- Diagnostic Markers for Early Detection of Ovarian Cancer. Clinical Cancer Research 14(4) Online 15 February 2008: 1065-10