Declining CA-125 in an ovarian cancer patient with progression of measurable disease: A rational hypothesis for discordant results

Objectives. While a declining CA-125 has been demonstrated to be a useful i ndicator of response to chemotherapy in ovarian cancer, occasional patients will demonstrate discordant results between the level of this antigen and changes in the size of measurable tumor masses. Case. The patient was seen in the Gynecologic Oncology Program of the Cleve land Clinic Taussig Cancer Center. Results. This patient exhibited a "major response" by CA-125 criteria, sign ificant shrinkage of multiple peritoneal and perirectal implants, but clear progression of a pelvic side wall mass. The discordant results in this cas e are likely an example of a "mixed response" to the chemotherapy regimen, with the declining CA-125 corresponding to shrinkage of the responding tumo r cell population. Conclusion. An evaluation of changes in both the serum CA-125 level and mea surable masses may represent a more complete analysis of the status of dise ase in an individual with ovarian cancer. (C) 2000 Academic Press.