Objective: While the clinical utility of the serum CA-125 antigen level in demonstrating objective evidence of regression or progression of disease in women with ovarian cancer is well-established, the relationship between both the absolute value of this tumor maker, or its rate of change over time, and the short-term clinical course (e.g., development of cancer-related symptoms) in individual patients remains poorly defined.
Case reports: Five women currently under the care of physicians in the Gynecologic Cancer program of the Cleveland Clinic demonstrate the marked variability in the correlation between the serum CA-125 antigen and the natural history of disease for individual patients with ovarian or primary peritoneal cancers. In these cases, persistent elevations (>100 units/ml for >2 years), rapid changes (<200 units/ml to >2000 units/ml over < or = 2 months), or extremely high CA-125 values (>5000 units/ml) failed to accurately predict the presence, time to development, or severity of symptoms.
Conclusion: In the second-line and palliative management of ovarian or primary peritoneal cancers, it is important to emphasize the critical need for clinical judgement in the decision to initiate or alter therapy in individual patients based solely on changes in the serum level of the CA-125 antigen.