Prospective multicenter study of bone scintigraphy in consecutive patients with newly diagnosed prostate cancer.

Background: International guidelines uniformly suggest no routine staging of bone metastasis in patients with bone scintigraphy (BS) in low-risk prostate cancer (PCa). These recommendations are based on retrospective investigations only. In addition, BS has most often been reported as a definitive investigation with no room for equivocal cases.

Objective: The objective of this study was to determine the diagnostic value of BS in a large cohort of consecutive patients with newly diagnosed PCa.

Design, Setting, And Participants: Over a period of 1.5 years in 2008 to 2009, consecutive patients with newly diagnosed PCa were enrolled in a noninterventional, multicenter, observational study. All patients had a whole-body, planar BS. Clinical history and clinical, pathological, and biochemical data were obtained from electronic patient files and questionnaires.

Outcome Measurements And Statistical Analysis: Bone scintigraphy was classified into 4 categories as nonmalignant, equivocal, likely malignant, or multiple metastasis. The primary end point was final imaging, which was a composite end point of BS and additional CT and MRI investigations.

Results And Limitations: A total of 635 eligible patients were recruited. Their median prostate-specific antigen (PSA) was 15 ng/mL, median Gleason was 7, and 80% of patients had local disease (T1 or T2). The proportion of nonmalignant BS was 61%, equivocal scans 26%, and likely or definitive metastasis 13%. A total of 154 patients had additional CT or MRI investigations. The final imaging diagnosis showed a prevalence of bone metastases in 87 (13.7%) of 635 patients. No bone metastases were observed in (1) patients with PSA of less than 10 ng/mL, independently of the clinical Tstage and Gleason score (n = 212) and (2) PSA of less than 20 ng/mL if Tstage is less than T3 and Gleason score is less than 8 (n = 97). Approximately 50% of the patients enrolled in this study met these criteria.

Conclusion: This is the first prospective trial to demonstrate that BS can be avoided in patients with low-risk PCa.