Known as the “silent killer,” ovarian cancer is the fifth leading cause of cancer-related death for women in the U.S. Despite being one-tenth as common as breast cancer, it is three times more lethal.
The high mortality of ovarian cancer is due to the lack of a screening strategy that can detect the early stages of the disease before most symptoms emerge.
From the early stages when the cancer is localized in the ovaries to the late stages when it has spread to other parts of the abdomen, the 10-yr survival rate after diagnosis drops from 90% to less than 20%.
To assist in earlier diagnoses, Gil Mor, M.D., Ph.D. and his lab in the obstetric and gynecology department of the Yale School of Medicine have recently developed a blood test that is 99% accurate.
The researchers tested the six biomarkers in blood samples from over 500 women, consisting of 362 healthy controls and 156 newly diagnosed ovarian cancer patients.
Current tests for ovarian cancer, consisting of ultrasounds and blood tests measuring the protein CA-125 (a cancer antigen), are only about 20% accurate in the early stages of the cancer.
The new diagnostic measures concentrations of six different proteins in the blood (leptin, prolactin, osteopontin, IGF-II, MIF and CA-125), so women can be diagnosed with high accuracy in the early stages before the survival rate drops.
The test is so effective because not only measures proteins levels directly from the tumor, but also measures multiple other proteins related to the normal physiology of the ovaries.
In the early stages before there are enough cancerous proteins in the blood to measure, the body responds to a tumor by significantly altering the amounts of these regular proteins.
In addition, the test uses multiplex, a new technology that allows one single reaction to detect the proteins. According to Mor, multiplex is “more simple, cheaper, faster, and has the same or better sensitivity than ELISA,” currently the most common procedure used to detect the presence of specific proteins.
Individually, the proteins cannot serve as a reliable indicator of cancer. “There is no magic protein” said Mor, “but the six proteins together represent a unique profile for ovarian cancer.”
Early detection of ovarian cancer will lead to a major decrease in mortality from the disease, and Mor hopes his test will become a standard procedure for women during their routine examinations.
Since the disease develops relatively slowly, the hope is that an annual test will detect the cancer during its early stages. “Think of it like a mammogram,” Mor said, comparing it to annual tests which have been extremely successful in diagnosing breast cancer in its early, treatable stages.
Diagnoses of ovarian cancer currently peak at age 65, so Mor suggested annual screenings begin at age 55 for low-risk women and even earlier for women with a family history of ovarian, breast, or colon cancer.
The test is already in use at Yale, and has been licensed in the U.S. to LabCorp, who will soon commercialize it after additional trials.