CA-125 values predictive of clinical response during second-line chemotherapy for epithelial ovarian cancer

Between November 1984 and January 1987, 19 patients with epithelial ovarian cancer were monitored with CA-125 values during second-line therapy. There was a statistically significant association between clinical response to therapy and CA-125 trend when trend was defined as a greater than or equal to 26% change in CA-125 from baseline value to last value prior to demonstration of clinical response (p = 0.0002). In 8 of 11 patients (73%), increasing CA-125 values were predictive of clinical progression during second-line therapy. In six of seven patients (86%), decreasing values predicted clinical regression. Three patients began second-line therapy with baseline values less than 35 U/ml. Two of these progressed during second-line therapy while the third progressed in follow-up. Two of four complete clinical responders completed second-line therapy with values less than 35 U/ml. Both progressed in follow-up with increasing CA-125 values. In this analysis, a 26% change in CA-125 values was a useful predictor of clinical response in patients receiving second-line therapy for epithelial ovarian cancer. Patients undergoing second-line chemotherapy with values less than 35 U/ml may still benefit from CA-125 monitoring.