The positive yield of imaging studies in the evaluation of men with newly diagnosed prostate cancer: a population based analysis.

Purpose: We determine the positive yield of imaging studies performed on men with newly diagnosed prostate cancer.
Materials and Methods: A prospective, population based survey was conducted on 3,690 men with prostate cancer diagnosed between October 1, 1994 and October 31, 1995. Cases were identified by the rapid case ascertainment systems used in 6 geographic regions participating in the Surveillance, Epidemiology and End Results Program. Based on information captured in primary medical record reviews we estimated the positive yield of bone scans, computerized tomography (CT) and magnetic resonance imaging.
Results: The positive yield of bone scan and CT was less than 5% and 12%, respectively, for all men with prostate specific antigen (PSA) 4 to 20 ng./ml., and less than 2% and 9%, respectively, for those who also had a Gleason score of 6 or less. Only men with PSA greater than 50 ng./ml. and those with Gleason scores 8 to 10 and PSA greater than 20 ng./ml. had positive yields greater than 10% and 20% for bone scan and CT, respectively.
Conclusions: Imaging studies designed to identify metastases and/or extracapsular extension in men with newly diagnosed prostate cancer frequently have a low positive yield. Wide variations exist in the use of imaging studies and are associated with tumor factors, such as Gleason score and serum PSA, and nontumor factors, such as state of residence. More extensive cost-effectiveness analyses are needed to define appropriate guidelines for ordering imaging studies to optimize the positive yield among men with newly diagnosed prostate cancer.