CA 125 in monitoring chemotherapy of patients with ovarian cancer: early response to the treatment.

Using an immunoenzymatic technique, changes in serum levels of CA 125 were examined in 63 patients with ovarian carcinoma before treatment as well as following the first four courses of chemotherapy. Serum CA 125 level before treatment was dependent upon clinical advancement stage (20.0, 393.43 and 688.84 U/ml at the Stages I + II, III and IV, respectively). Good response to treatment was associated with decreased CA 125 levels, while tumor progression was linked to increasing levels of the marker. Treatment scheme including cisplatinum induced most pronounced decrease in serum CA 125 level which paralleled good clinical response to the treatment. Determination of CA 125 half-life time in serum seemed to provide a sensitive prognostic index in the disease. This index amounted to 10.73 +/- 4.0 days in patients with complete remission and 44.87 +/- 26.5 days in patients with progressive disease.