First, let’s define a few key words:
- CA125: A protein found on the surface of many ovarian cancer cells. Most women with ovarian cancer have CA125 levels in the blood that are over 35.
- ROCA: An abbreviation for Risk of Ovarian Cancer Algorithm, a test that assesses risk for developing ovarian cancer. This test tracks CA125 levels over time to identify significant elevations above each patient’s baseline levels.
What’s the issue researchers wanted to address? The standard advice for women at high risk of ovarian cancer, due to either family history or inherited gene mutations, is to have their ovaries and fallopian tubes surgically removed as a preventative measure once they are done having children. Some women choose to postpone this surgery and there’s a need for a screening test for these women that will detect the development of tumors while the cancer is still in a treatable stage.
How did they address this issue? Researchers from the Massachusetts General Hospital (MGH) Cancer Center and the Biostatistics Unit, and the National Cancer Institute and Anderson Cancer Center enrolled more than 3,800 women at elevated risk for ovarian cancer in two screening trials. Participants had blood tests every three months to establish their baseline levels of CA125 and to monitor for any changes using the ROCA assessment tool. Women at intermediate ROCA risk were referred for an ultrasound examination, while those at an elevated ROCA risk received both ultrasound and clinical evaluation.
What did they find? 19 malignant tumors of the ovaries or fallopian tubes were identified during the study periods. Ten cases were diagnosed during screening, and nine were diagnosed by preventive surgery. This protocol increased the proportion of tumors detected at early stages from 10 percent – which is typically seen in high-risk women who are not screened – to 50 percent.
What do these results mean? The combined results of the two screening trials suggest that a protocol involving quarterly blood testing to identify significant increases above each patient’s personal baseline in levels of CA125, followed by ultrasound examination when such elevations are detected, could improve the chance that tumors are detected at early stages when they are easier to treat.
What do researchers have to say about their findings? Researchers caution that surgery is the primary and best option for reducing the risk of ovarian cancer, and ROCA should only be considered as a promising but unproven option for patients who decide, against medical advice, to postpone their surgery. They plan to conduct more research to identify other ovarian cancer indicators and improved imaging technologies that may help to detect even more tumors at even earlier stages.
Steven Skates, PhD, of the Massachusetts General Hospital (MGH) Cancer Center and the Biostatistics Unit, is co-lead and corresponding author of the report. Learn more here.