Limited value of bone scintigraphy and computed tomography in assessing biochemical failure after radical prostatectomy.

ABSTRACT

OBJECTIVES: To define the utility of bone scan and computed tomography (CT) in the evaluation of patients with biochemical recurrence after radical prostatectomy. METHODS: A retrospective analysis of the Center for Prostate Disease Research database was undertaken to identify patients who underwent radical prostatectomy between 1989 and 1998. Patients who developed biochemical recurrence (two prostate-specific antigen [PSA] levels greater than 0.2 ng/mL) and underwent either bone scan or CT within 3 years of this recurrence were selected for analysis. The preoperative clinical parameters, pathologic findings, serum PSA levels, follow-up data, and radiographic results were reviewed. RESULTS: One hundred thirty-two patients with biochemical recurrence and a bone scan or CT scan were identified. Of the 127 bone scans, 12 (9.4%) were positive. The patients with true-positive bone scans had an average PSA at the time of the bone scan of 61.3 +/- 71.2 ng/mL (range 1.3 to 123). Their PSA velocities, calculated from the PSA levels determined immediately before the radiographic studies, averaged 22.1 +/- 24.7 ng/mL/mo (range 0.14 to 60.0). Only 2 patients with a positive bone scan had a PSA velocity of less than 0.5 ng/mL/mo. Of the 86 CT scans, 12 (14.0%) were positive. On logistic regression analysis, PSA and PSA velocity predicted the bone scan result (P <0.001 each) and PSA velocity predicted the CT scan result (P = 0.047). CONCLUSIONS: Patients with biochemical recurrence after radical prostatectomy have a low probability of a positive bone scan (9.4%) or a positive CT scan (14.0%) within 3 years of biochemical recurrence. Most patients with a positive bone scan have a high PSA level and a high PSA velocity (greater than 0.5 ng/mL/mo).