Effects of paclitaxel on CA-125 serum levels in ovarian cancer patients

Objective. As in vitro activation of ovarian carcinoma cells in terms of CA -125 secretion by taxanes has been demonstrated, we were interested in whet her taxanes also modulate CA-125 expression in vivo. Methods. Serum CA-125 was determined immediately before and 24 h after pacl itaxel-containing chemotherapy in 53 ovarian carcinoma patients. To test th e quality of the analysis methods and the biological variation of untreated patients, serum CA-125 levels of two control groups were analyzed. Results. Median CA-125 concentration was 107 kU/liter 24 h after chemothera py treatment compared with 99 kU/liter the day before paclitaxel treatment. Changes in CA-125 serum levels observed immediately after paclitaxel treat ment were not correlated to treatment response. However, overall change in CA-125 serum concentration was a good predictor of response to paclitaxel c ontaining treatment. Patients achieving a complete or partial response had a significant reduction of median CA-125 levels, whereas tumor progression was associated with increased CA-125 levels. Only for the group of patients obtaining a complete response was a decrease in the median relative CA-125 value observed. Conclusion. Paclitaxel-induced modulation of CA-125 expression could not be confirmed in vivo. (C) 2000 Academic Press.