Blood Test Best for Predicting Ovarian Cancer Survival

The study, published in the September 13, 2004 issue of the Journal of Clinical Oncology, is the first to compare the two modalities with respect to survival.

CT scans and other imaging modalities are frequently utilized in patients with recurrent tumors to evaluate whether the patient is responding to treatment. Response Evaluation Criteria in Solid Tumors (RECIST), the standard criteria for studying CT scans and ultrasonography, evaluates treatment response by measuring the growth or shrinkage of the tumor.

Unlike other solid tumors, however, ovarian tumors spread diffusely through the abdomen, making tumor tissue much more difficult to detect through CT scans. Because of this, response cannot always be evaluated by the RECIST criteria. Investigators theorize that the CA125 blood test might be a better method for assessing tumor growth among patients whose tumors have returned than conventional imaging techniques. To compare the two modalities, the researchers used the RECIST criteria and a set of criteria for the CA125 blood test, which evaluates treatment response according to CA125 protein levels present in the blood.

Utilizing one of the world's largest database of patients with recurrent ovarian cancer, investigators retrospectively evaluated 131 patients receiving topecan or paclitaxel-carboplatin as a second-line chemotherapy. Investigators discovered that the CA125 criteria were 2.6 times more accurate than RECIST in predicting survival, and concluded that in selected patients, tumor-marker guided response criteria such as CA125 may be better than imaging-based response criteria in evaluating the outcome of second-line chemotherapy.

Nevertheless, investigators remarked that the study results are only appropriate for patients treated with paclitaxel-carboplatin or topecan, and stressed the necessity for a randomized trial that included additional targeted therapies or chemotherapeutic agents and that evaluates RECIST and CA125 in predicting both quality of life and survival.

"The CA125 response criteria has great potential value in clinical trials. Increased confidence in a CA125 response definition should lead to a cheaper, and in some cases, more accurate method for monitoring ovarian cancer therapy than standard radiographic criteria,” remarked Prof. Gordon J.S. Rustin of Mount Vernon Cancer Center (Middlesex, UK) in an editorial in the same issue of the Journal of Clinical Oncology.




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