PROGNOSTIC-SIGNIFICANCE OF THE CA-125 INI TIAL HALF-LIFE MEASURED DURING FIRST-LINE CHEMOTHERAPY IN 62 PATIENTS WITH EPITHELIAL OVARIAN-CANCER STAGE-III OR STAGE-IV

The prognostic value of CA 125 initial half-life in serum (Tb) during the first cycles of first-line chemotherapy was studied in 62 patients with stage III or IV ovarian cancer. The half-life was strongly corre lated; 1) with the rate of biological remission (P < 0.001). This one was respectively equal to 94.7% when Tb was lower than 20 days, 66.6% when Tb was between 20 and 40 days and 7.7% when Tb was higher than 40 days; 2) with the rate of histological remission (P < 0.001) which wa s equal to 66.6% when Tb was lower than 13 days; 3) with the speed of recurrence growth measured by the doubling time (dT) of CA 125. The me dian of dT was equal to 182 days when Tb was lower than 13 days, 63 da ys when Tb was between 13 and 20 days (P < 0.02) and 38 days when Tb w as higher than 20 days (P < 0.001); 4) with the duration of disease-fr ee survival (DFS) (P < 0.0001): the medians were equal to 23.9 months, 18.0 months, 12.0 months, and 5.5 months, respectively, where Tb was lower than 13 days, between 13 and 20 days; 20 and 40 days, and higher than 40 days; and 5) with the duration of overall survival (OS). The probability of survival at five years was equal to 48% when Tb was low er than 13 days. This probability falled to 13%, 12%, and 8%, when Tb was respectively between 13 and 20 days, 20 and 40 days and higher tha n 40 days. Multiple regression analysis showed that CA 125 half-life w as the most important prognostic factor for DFS and OS. Analysis of co rrelation allowed to identify a relation between: 1) dT and Tb [Td = T b/[-0,305 + (0,0388)(Tb)]; P < 10(-4)]; 2) the slope of CA 125 initial regression (P) and DFS [DFS = 201, 9e (-16,64P); P < 10(-8)]; 3) P a nd OS [OS = 285.0e(-17,00P); P < 10(-7)]. The initial CA 125 half-lif e measured during the first cycles of first time chemotherapy seemed t o be a critical predictor of response to therapy.