Bone scan in initial staging of prostate cancer.

Bone scans of 64 patients with newly diagnosed prostate cancer were retrospectively analysed. Metastases were present in 29 patients (45%). In 75% of these cases, the pattern was manifeastly metastatic. The third threshold has high negative and positive predictive values. The topography of metastatic lesions is in favour of a systemic spread. There were no metastatic cases with a PSA level under 10 ng/ml. Multiple IAU and intense IAU are the most specific patterns of metastatic lesions. Also, focal lesions on sacroiliacs are also in favour of metastatic origin. The distribution of metastases is globally similar to that of the bone marrow in adult and systemic spread is the most probable. Staging bone scan must be reserved to patients with PSA level greater than 10 ng/ml, poorly degree of differentiation and advanced clinical stage.