A new study shows that the CA125 blood test, which measures the level of protein produced by ovarian cancer cells in the blood, may be superior to standard imaging techniques like CT scans in predicting survival in patients with recurrent ovarian cancer.
The study, to be published online September 13 in the Journal of Clinical Oncology, is the first to compare the two procedures with respect to survival.
"This is good news for patients – our study indicates that selected patients can be safely monitored by blood tests alone and thus avoid costly and time consuming CT scans," said Bo Gronlund, MD, lead author and head of the CODOVA database at the Department of Oncology at Rigshospitalet, the Copenhagen University Hospital.
CT scans and other imaging techniques are often used in patients with recurrent cancer to assess whether the patient is responding to treatment. RECIST, the standard criteria for analyzing CT scans and ultrasonography, assesses treatment response by measuring the growth or shrinkage of the tumor.
However, unlike other solid tumors, ovarian cancer spreads diffusely through the abdomen, making tumor tissue much more difficult to detect through CT scans. As a result, response cannot always be measured by RECIST criteria.
Researchers hypothesized that the CA125 blood test might be a better tool for observing tumor growth among patients whose cancer has returned than traditional imaging techniques. To compare the two procedures, they used the RECIST criteria and a set of criteria for the CA125 blood test, which assesses treatment response according to the level of CA125 protein present in the blood.