Do all patients with newly diagnosed prostate cancer need staging radionuclide bone scan? A retrospective study

Define a group of patients with newly diagnosed prostate cancer, whose risk of bone metastasis is low enough to omit a bone scan staging study.

From 2003 to 2009, the medical records of patients who were newly diagnosed with prostate cancer were retrospectively reviewed. The data collected included: age, digital rectal examination, serum prostate specific antigen (PSA), Gleason score, clinical T stage, and bone isotope scan. Patients were divided into two groups according to the results of bone isotope scan; positive group and negative group. A univariate and multivariate binary logistic regression was used to analyze the results.

Of the 106 patients, 98 had a complete data collection and were entered into the study. The median age of the patients was 70.5 years and patients with a positive bone scan was 74 years, significantly higher than for patients with negative scans (69 years) (p=0.02). Bone metastasis was detected in 39 cases (39.7%). In all patients with clinical T1-2 stage, a Gleason score of <8 and PSA≤20 ng/mL, the bone isotope scans were negative. In univariate analysis, PSA (>20 ng/mL) and Gleason score (>7) were independently predictive of positive bone scan, while clinical stage was not.

Staging bone scans can be omitted in patients with a PSA level of ≤20 ng/mL, and Gleason score<8. Our results suggest that by considering the Gleason score and PSA, a larger proportion of patients with prostate cancer could avoid a staging bone scan.