Which patients with newly diagnosed prostate cancer need a computed tomography scan of the abdomen and pelvis? An analysis based on 588 patients

Abstract

Objectives. Although a computed tomography (CT) scan of the abdomen and pelvis is often recommended as part of the staging evaluation for newly diagnosed prostate cancer, most scans are negative for metastases. We hypothesized that biopsy Gleason score, serum prostate-specific antigen (PSA) levels, and clinical stage could predict for a positive CT scan and that a low-risk group of patients could be identified in whom CT might be omitted. Methods. All patients who had both pathologic review of their prostate cancer biopsies and abdominopelvic CT scans at our institution between January 1990 and May 1996 were studied. Gleason score, PSA, and stage were evaluated by univariate (chi-square) and multivariate (logistic regression) analyses for their ability to predict for a positive CT. Results. Of 588 patients, 41 (7%) had a positive CT scan. Multivariate analysis showed Gleason score, PSA, and clinical stage to be significant independent predictors of a positive CT scan, all P <0.001. The odds ratios for a positive CT scan were 6.17 (95% confidence interval [CI] = 1.58 to 24) for Gleason score 8 to 10 versus 2 to 6; 2.25 (CI = 1.24 to 4) for PSA greater than 50 versus 0 to 15 ng/mL; 2.08 (CI = 1.70 to 3.21) for Stage T2c-T4 versus T2b or lower. All 244 patients with Gleason score 2 to 7, PSA 15 ng/mL or less, and clinical Stage T2b or less had negative CT scans. Of the other 174 patients with a Gleason score of 2 to 7, 8 (5%) had a positive CT scan. Of the 126 patients with a Gleason score of 8 to 10, 28 (22%) had a positive CT scan. Conclusions. Gleason score, PSA, and clinical stage were independent predictors for a positive CT scan of the abdomen and pelvis in patients with newly diagnosed prostate cancer. In this cost-conscious era, we can decrease expenditure by obviating the need for a CT scan in low-risk patients (clinical Stage T2b or less, Gleason score 2 to 7, and PSA 15 ng/mL or less). A CT scan should be considered in all other patients.