CA-125 blood test best for predicting outcome of ovarian cancer

The cancer antigen (CA) -125 response criteria set forth by the Gynecologic Cancer Intergroup (GCIG) is better than standard CT/ultrasound-based criteria at predicting survival in ovarian cancer patients receiving second-line chemotherapy, according to Danish researchers.

“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,” lead author Dr. Bo Gronlund, from Rigshospitalet in Copenhagen, said in a statement.To determine which criteria represented a better prognostic tool, Dr. Gronlund’s team analyzed data from 68 patients who received second-line chemotherapy involving topotecan or paclitaxel plus carboplatin. The findings appear in the September 13th online issue of the Journal of Clinical Oncology. With the CT/ultrasound-based criteria, known as the Response Evaluation Criteria in Solid Tumors (RECIST), a treatment response is defined as a drop in the baseline sum longest tumor diameter of at least 30%. With the GCIG criteria, by contrast, a response is defined as fall in elevated CA-125 levels of at least 50%.The CA-125 criteria were 2.6 times more accurate than RECIST at predicting survival, the investigators note. Moreover, on multivariate analysis, the CA-125 response remained a significant predictor of survival, whereas the RECIST response did not.In a related editorial, Dr. Gordon J. S. Rustin, from Mount Vernon Cancer Centre in Northwood, UK, comments that “increased confidence in a CA-125 response definition should lead to a cheaper and, in some cases, more accurate method for monitoring ovarian carcinoma therapy than standard radiographic criteria.”(Source: J Clin Oncol 2004;22: Reuters Health News: Oncolink: September 2004.)