Systematic Review of Monitoring Criteria to Interpret CA125 Increments during First-Line Chemotherapy and the Subsequent Follow-Up Period among Patients with Advanced Epithelial Ovarian Cancer
Background: Optimal clinical management of ovarian cancer patients requires prompt and accurate determination of whether primary or recurrent disease is responding to chemotherapy. If CA125 is to fill this need, we must understand the design and outcomes of clinical trials that have established a correlation between CA125 levels and growth or shrinkage of tumor burden. It is particularly important to define the magnitude of changes in CA125 concentrations that indicate cancer growth and prompt cessation of ineffective therapy. Objective: To review clinical trials which test the ability of CA125 to monitor ovarian cancer growth during chemotherapy for primary disease and detection of recurrence. Methods: The Medline and Embase databases were searched for original articles published in English between January 1982 and May 2014 that evaluated the utility of CA125 for monitoring ovarian cancer growth. Results: CA125 was evaluated in 13 reports during primary therapy and in eight reports during subsequent follow-up. CA125 sensitivity for detecting tumor growth was not reported consistently, but could be calculated from data provided in the articles. During primary therapy, the median sensitivity for recurrence was 60% (range 33%-95%) and during follow-up the median sensitivity was 85% (range 62%-93%). Conclusion: Consistent criteria for indicating disease progression with CA125 could not be defined due to differences in trial design and selection of patients. The most promising criteria should be re-evaluated under similar and standardized conditions. Computer simulation models and change point algorithms may aid in identifying CA125 assessment criteria to be further validated in prospective clinical trials.