When is a bone scan study appropriate in asymptomatic men diagnosed with prostate cancer?

To determine when a bone scan investigation is appropriate in asymptomatic men diagnosed with prostate cancer.

Between November 2005 and July 2006, 317 men with prostate cancer underwent a bone scan study; 176 men fulfilled the inclusion criteria. Prostate-specific antigen (PSA) cut-offs as well as univariate and multivariate logistic regression analyses using digital rectal examination finding, biopsy Gleason scores and age were performed to determine when a bone scan study is likely to be of value.

Only 1/61 men (1.6%) with a serum PSA 20 ng/mL had a positive bone scan. However, 2/38 men (4.7%) with a serum PSA 20.1-40.0 ng/mL, 3/20 men (15%) with a serum PSA 40.1-60.0 ng/mL, 7/19 men (36.8%) with a serum PSA 60.1-100.0 ng/mL and 19/38 men (50%) with a serum PSA > 100.0 ng/mL had positive bone scans. Univariate and multivariate logistic regression analyses were uninformative in these groups.

Based on our findings, a bone scan is of limited value in asymptomatic prostate cancer patients presenting PSA =or< 20 ng/mL. Therefore, this investigation can be eliminated unless a curative treatment is contemplated. Furthermore, digital rectal examination finding, biopsy Gleason score and age are unhelpful in predicting those who might harbor bone metastasis.