Which patients with newly diagnosed prostate cancer need a radionuclide bone scan? An analysis based on 631 patients

Purpose: Although radionuclide bone scans are frequently recommended as par t of the staging evaluation for newly diagnosed;prostate cancer, most scans are negative for metastases. We hypothesized that Gleason score, prostate- specific antigen (PSA), and clinical stage could predict for a positive bon e scan (BS), and that a low-risk group of patients could be identified in w hom BS might be omitted. Methods: All patients who had both pathologic review of their prostate canc er biopsies and radionuclide BS at our institution between 1/90 and 5/96 we re studied. Gleason score, PSA, and clinical stage (AJCC, 4th edition) were evaluated by univariate and multivariate analyses for their ability to pre dict a positive BS. Groups analyzed were Gleason of 2-6 vs. 7 vs. 8-10; PSA of 0-15 vs. greater than 15-50 vs. greater than 50; and clinical stage of T1a-T2b vs. T2c-T4. Univariate analysis using chi (2) and multivariate anal ysis using logistic regression were performed. Results: Of the 631 consecutive patients, 88 (14%) had positive BS. Multiva riate analysis (64 excluded due to missing PSA and/or clinical stage) showe d Gleason score, PSA, and clinical stage to be significant independent pred ictors for positive BS (p < 0.002, p < 0.001, p < 0.001, respectively). The odds ratios were 5.25 (confidence interval [CI], 3.43-8.04) for PSA > 50 v s. 0-15; 2.25 (CI, 1.43-3.54) for Gleason of 8-10 vs. 2-6; 2.15 (CI, 1.54-2 .99) for clinical stage T2c-T4 vs. T2b or less. Three of 308 (1%) had a pos itive BS in patients with Gleason 2-7, PSA of 50 or less, and clinical stag e of T2b or less. In the subset of the same risk group with PSA of 15 or le ss, all 237 had negative bone scans. In patients,vith PSA greater than 50, 49/99(49.5%) had positive BS. Conclusion: Gleason score, PSA, and clinical stage were independent predict ors for a positive radionuclide BS in newly diagnosed prostate cancer patie nts. PSA is the major predictor for positive BS. About one-half of the pati ents analyzed were in the low-risk group (Gleason 2-7, PSA less than or equ al to 50, clinical stage less than or equal to T2b) and elimination of BS i n these patients would result in considerable economic savings. (C) 2000 El sevier Science Inc.