The predictive and prognostic value of serum CA 125 half-life during paclitaxel/platinum-based chemotherapy in patients with advanced ovarian carcinoma.

OBJECTIVES: Serum CA 125 kinetics during early chemotherapy has a strong predictive and prognostic relevance for patients with advanced ovarian carcinoma who received a first-line platinum-based regimen, whereas the ability of serum CA 125 assay to reflect the response to paclitaxel-based chemotherapy has not yet been defined. The aim of the present paper is to calculate the serum CA 125 half-life during first-line paclitaxel/platinum-based chemotherapy in patients with advanced ovarian carcinoma and to correlate this kinetic parameter with the response to treatment, progression-free survival and overall survival.

METHODS: This retrospective investigation assessed 71 patients with stages IIc-IV ovarian carcinoma who underwent initial surgery followed by paclitaxel/platinum-based chemotherapy and who had serum CA 125 > 35 U/ml before the first cycle of chemotherapy. Only epithelial ovarian cancers were included.

RESULTS: The 25%, 50%, and 75% quantiles of serum CA 125 half-life during early chemotherapy were 10, 14, and 20 days, respectively. Taking the value corresponding to the 50% quantile (i.e., 14 days) as cutoff limit, serum CA 125 half-life was an independent prognostic factor for the chance of achieving a complete response to treatment as well as for progression-free survival and overall survival. In detail, patients with serum antigen half-life <== 14 days had a 3.362 times as great probability to achieve a complete response and a 3.113 times as low probability to die when compared to those with a longer half-life.

CONCLUSIONS: Serum CA 125 assay represents a reliable biochemical tool for the management of advanced ovarian carcinoma patients who receive a first-line paclitaxel/platinum-based chemotherapy.