THE IMPACT OF CA-125 ON THE SENSITIVITY OF ABDOMINAL PELVIC CT SCAN BEFORE 2ND-LOOK LAPAROTOMY IN ADVANCED OVARIAN-CARCINOMA

For ovarian carcinoma patients with an elevated CA-125 level at diagno sis, elevation of the antigen at the time of second-look laparotomy is consistently associated with persistent disease. This study was under taken to determine the sensitivity and specificity of abdominal/pelvic CT scans for persistent ovarian carcinoma in patients with normal CA- 125 levels before second-look laparotomy. Forty-five patients with sta ge III and IV ovarian carcinoma who had CA-125 levels obtained prior t o initial surgery, CA-125 values <35 IU ml(-1) after chemotherapy and underwent a second-look laparotomy, were studied. Forty patients with initially elevated CA-125 levels normalized their CA-125 levels during chemotherapy. Five patients with normal initial CA-125 levels had val ues <35 IU ml(-1) at the completion of chemotherapy. CT scans were cla ssified as definitively positive, suspicious or negative and were comp ared with second-look laparotomy results. Only two of the 45 patients (4.4%) had a positive scan which could be confirmed by CT-directed bio psy. In the 40 patients with initially elevated CA-125 levels, the sen sitivity for abdominal/pelvic CT scans was only 10%. The negative pred ictive value was not altered by analyzing initial CA-125 values at cri tical values of 35, 100 and 500 IU ml(-1). Among patients with CA-125 levels <35 IU ml(-1) prior to initial treatment, four had no evidence of persistent disease on CT scan or second-look surgery and one patien t with a suggestive CT scan had small volume disease (2 mm) at second- look laparotomy. For all 45 patients, when scans suggestive for persis tent disease were included, CT scans had a sensitivity of 52% and a sp ecificity of 75%. The addition of CA-125 testing decreased the sensiti vity of abdominal/pelvic CT scanning for persistent disease. CT scanni ng is most likely to be of assistance in patients with liver or nodal disease or bulky residual disease after primary cytoreduction, since t his disease is more likely accessible to CT-directed biopsy. Patients with negative CA-125 levels prior to initial surgery may also benefit.