MONITORING CANCER ANTIGEN-125 LEVELS IN INDUCTION CHEMOTHERAPY FOR EPITHELIAL OVARIAN-CARCINOMA AND PREDICTING OUTCOME OF 2ND-LOOK PROCEDURE

A retrospective analysis of 45 patients with epithelial ovarian carcin oma who underwent second-look procedure after initial cytoreduction an d platinum-based combination chemotherapy was undertaken. Each patient was evaluated for the result of CA 125 after a third course of chemot herapy, the result of CA 125 prior to second-look laparotomy, and the calculated slope of regression curve for CA 125. These results were co mpared for a normal value of CA 125 of <35 and <20 IU/ml. Of the 45 pa tients who underwent second-look procedure, 27 had a positive outcome, while 18 were negative for residual disease. For CA 125 levels obtain ed after the third course of chemotherapy, a level greater than or equ al to 35 IU/ml mi predicted a positive second-look outcome in three pa tients, but was not statistically significant (P = 0.143) when compare d to patients with normal levels. Of patients with CA 125 greater than or equal to 35 IU/ml immediately prior to second-look procedure, nine had a positive outcome for second look, a difference that was statist ically significant (P = 0.006) when compared to patients with normal l evels. For the calculation of the slope of the regression curve, no st atistical difference (P = 0.838) was observed between the average of t he slopes of the positive-outcome group and that the negative-outcome group. The only useful prediction of second-look procedure outcome ide ntified in this group of patients was an elevated (greater than or equ al to 35 IU/ml) CA 125 immediately prior to second-look procedure. Ele vated levels at this time predicted the presence of disease in 100% of patients. For the other methods of analyzing CA 125 levels during the rapy, the outcome of second look could not be predicted in patients wi th no clinical evidence of disease. Selecting a lower normal level of 20 IU/ml did not increase our ability to predict second-look procedure outcome. (C) 1995 Academic Press, Inc.