The impact of CA-125 on the sensitivity of abdominal/pelvic CT scan before second-look laparotomy in advanced ovarian carcinoma

Abstract

Rose PG, Reuter KL, Nelson BE, Sirois J, Fournier L, Reale FR, Hunter RE. The impact of CA-125 on the sensitivity of abdominal/pelvic CT scan before second-look laparotomy in advanced ovarian carcinoma. Int J Gynecol Cancer 1996; 6: 213-218. For ovarian carcinoma patients with an elevated CA-125 level at diagnosis, elevation of the antigen at the time of second-look laparotomy is consistently associated with persistent disease. This study was undertaken 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 stage III and IV ovarian carcinoma who had CA-125 levels obtained prior to initial surgery, CA-125 values <35 IU m1-1 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 values < 35 IU m1-1 at the completion of chemotherapy. CT scans were classified as definitively positive, suspicious or negative and were compared with second-look laparotomy results. Only two of the 45 patients (4.4%) had a positive scan which could be confirmed by CT- directed biopsy. In the 40 patients with initially elevated CA-125 levels, the sensitivity for abdominal/pelvic CT scans was only 10%. The negative predictive value was not altered by analyzing initial CA-125 values at critical values of 35, 100 and 500 IU m1-1. Among patients with CA-125 levels <35 IUm1-1 prior to initial treatment, four had no evidence of persistent disease on CT scan or second-look surgery and one patient with a suggestive CT scan had small volume disease (2 mm) at second-look laparotomy. For all 45 patients, when scans suggestive for persistent disease were included, CT scans had a sensitivity of 52% and a specificity of 75%. The addition of CA-125 testing decreased the sensitivity of abdominal/pelvic CT scanning for persistent disease. CT scanning is most likely to be of assistance in patients with liver or nodal disease or bulky residual disease after primary cytoreduction, since this disease is more likely accessible to CT-directed biopsy. Patients with negative CA-125 levels prior to initial surgery may also benefit.