New Ovarian Cancer Test Has Sweet Side
Ovarian cancer is not an easy disease to detect, and the fact that the most commonly used ovarian cancer test is unreliable is one reason why this is true. Now a research team has developed a new testing approach with a sweet side that offers a dramatic improvement.
Currently, the most common way to screen for ovarian cancer is a blood test that measures levels of a substance called CA-125 (cancer antigen 125). Elevated levels suggest the presence of ovarian cancer, but they also can indicate other conditions.
The CA-125 test is not reliable, however. It provides a true positive result only about 50 percent of the time for women who have stage I ovarian cancer and 80 percent of cases of stages II III, and IV ovarian cancer.
The high false positive rate associated with the CA-125 screening can cause a significant amount of stress and anxiety in women, who then need to undergo additional testing to determine whether they truly have the disease. Other conditions that can cause false positive results include first trimester of pregnancy, benign ovarian cysts, endometriosis, pelvic inflammatory disease, cirrhosis, pancreatic cancer, and other malignancies.
Sweet approach to ovarian cancer testing
Rather than test for the protein CA-125, the new approach, proposed by Ola Blixt, a chemical glycobiology (“glycol” means sugar) professor at the Department of Chemistry, University of Copenhagen (UC), and Professor Usha Menon, both of whom headed teams at UC and University College London, looks at sugar. According to Blixt, the sugar in question is found on the surface of the CA-125 protein of women who really have ovarian cancer.
The connection between sugar and cancer has been well-established, and this find is just one example of that relationship. Blixt notes that experts can detect chemical changes in the sugar layer on proteins when cancer is present, and that “it is very simple to investigate and determine the presence of this transformed sugar coating.”
How simple? Blixt and his team have already identified two inexpensive and readily available substances that can reveal the sugar. Rather than seek a patent on the approach, the researchers have published their findings and are hoping industry takes over and makes the test available.
“Any manufacturer is able to include this in their existing kit,” stated Blixt in a UC release. “And I hope that it happens soon.”
If the new test is brought to market, it would be a welcomed addition to the meager chest of screening tools for ovarian cancer. In addition to the CA-125 test, intravaginal ultrasound can be used.
This test involves inserting a probe into the vagina, where it emits sound waves and allows clinicians to get an image of the uterus, ovaries, and cervix. Intravaginal ultrasound is also performed to detect cysts and fibroid tumors and to help diagnose women suffering with pelvic pain, ectopic pregnancy, irregular bleeding, and infertility.
An estimated 22,240 women were diagnosed with ovarian cancer in 2013, according to the National Cancer Institute, yet about five times that number are told they may have cancer after they undergo initial screening. Introduction of a new ovarian cancer test would be a bitter sweet addition to medicine.
National Cancer Institute
University of Copenhagen
Image: Flickr/SantaRose OLD SKOOL