Washington, May 21 (ANI): CA-125, the protein long-recognized for predicting ovarian cancer recurrence, has now emerged as a promising tool for early-stage disease, found researchers at The University of Texas MD Anderson Cancer Center.
Dr. Karen Lu, said that if a larger study shows survival benefit, the simple blood test could offer a much-needed screening tool to detect ovarian cancer in it early stages - even in the most aggressive forms - in post-menopausal women at average risk for the disease.
"Over the last ten years, there's been a lot of excitement over new markers and technologies in ovarian cancer. I and other scientists in the gynaecologic oncology community thought we would ultimately find a better marker than CA-125 for the early detection of the disease. After looking at new markers and testing them head-to-head in strong, scientific studies, we found no marker better than CA125," said Lu.
For Lu, the challenge is that more than 70 percent of women with ovarian cancer are diagnosed with advanced disease.
"Finding a screening mechanism would be the Holy Grail in the fight against ovarian cancer, because when caught early it is not just treatable, but curable," said Lu.
For the prospective, single-arm study, 3,252 women were enrolled from seven sites across the US. All were healthy, post-menopausal women, ages 50-74, with no strong family history of breast or ovarian cancer.
The study's primary endpoint was specificity, or few false positives.
In addition, the study looked at the positive predictive value, or the number of operations required to detect a case of ovarian cancer.
Each woman received a baseline CA-125 blood-test.
Using the Risk of Ovarian Cancer Algorithm (ROCA), a mathematical model based on the patient's age and CA-125 score, women were stratified to one of three risks groups, with the respective follow-up: "low," came back in a year for a follow-up blood test; intermediate," further monitoring with repeat CA125 blood test in three months; and "high," referred to receive transvaginal sonography (TVS) and to see a gynecologic oncologist.
Cumulatively, 85 women (2.6 percent) were determined to be high risk, and thereby received the TVS and were referred to a gynecologic oncologist. Of those women, eight underwent surgery: five were found to have ovarian cancer, three with invasive and two with borderline disease; and three had benign tumors - a positive predictive value of 37.5 percent.
On the other hand, no more than three operations would be required to detect each case of ovarian cancer, explained Lu.
The screening failed to detect two borderline ovarian cancers.
Of great importance, said Lu, is that the three invasive ovarian cancers detected were high-grade epithelial tumors, the most aggressive form of the disease, and were caught early (stage IC or IIB), when the disease is not only treatable, but most often curable.
Lu also noted that all three women found to have invasive disease were monitored at low risk for three years or more prior to a rising CA-125.
"CA-125 is shed by only 80 percent of ovarian cancers. At present, we are planning a second trial that will evaluate a panel with four blood tests including CA-125 to detect the cancers we may otherwise miss with CA-125 alone. The current strategy is not perfect, but it appears to be a promising first step," explained Bast.
The study will be presented at the American Society of Clinical Oncology (ASCO) annual meeting. (ANI)