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.