Bone scan is of doubtful value as a first staging test in the primary presentation of prostate cancer

Purpose. To determine whether axial MR imaging could replace bone scan as the primary staging test in newly diagnosed CaP. Material and Methods. We reviewed retrospectively all bone scans (n = 1201) performed in newly diagnosed CaP patients from 2000 to 2010 in a single tertiary academic center. We recorded patient age, ethnicity, PSA at diagnosis, TNM stage, Gleason score, alkaline phosphatase, bone scan results and axial imaging if available. Results. Mean patient age was 72 years (41-96), mean PSA and alkaline phosphatase were 268.9 ng/mL and 166 IU/L, respectively. Patients were divided in four groups according to possible bony metastases on bone scan. Group 1: Negative, no metastases demonstrated. Group 2: Positive, metastases only in pelvis and/or lumbar spine. Group 3: Positive, widespread metastases including pelvis and lumbar spine. Group 4: Positive, distant metastases without pelvic or lumbar spine abnormalities. Group 4 patients were analyzed in detail, two had possible disease that was detected only outside the pelvic and lumbar spine, unfortunately follow up images were insufficient to confirm the nature of the lesions. Conclusions. Although bone scan is a useful investigation to confirm and monitor metastasic CaP, our data suggests that axial MR imaging is an adequate primary staging study in untreated disease. Bone scan is unnecessary if CT or MRI of the pelvis and abdomen are clear of metastases.