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 me n 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 O ctober 31, 1995. Cases were identified by the rapid case ascertainment syst ems used in 6 geographic regions participating in the Surveillance, Epidemi ology and End Results Program. Based on information captured in primary med ical record reviews we estimated the positive yield of bone scans, computer ized tomography (CT) and magnetic resonance imaging. Results: The positive yield of bone scan and CT was less than 5% and 12%, r espectively, for all men with prostate specific antigen (PSA) 4 to 20 ng./m l., 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 wi th Gleason scores 8 to 10 and PSA greater than 20 ng./ml. had positive yiel ds greater than 10% and 20% for bone scan and CT, respectively. Conclusions: Imaging studies designed to identify metastases and/or extraca psular extension in men with newly diagnosed prostate cancer frequently hav e 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-eff ectiveness analyses are needed to define appropriate guidelines for orderin g imaging studies to optimize the positive yield among men with newly diagn osed prostate cancer.