Should bone scan be performed in Chinese prostate cancer patients at the time of diagnosis?

Prostate cancer (PCa) is increasingly being diagnosed in China. Early detection of bone metastases (BM) is critical in the management of patients with high-risk PCa. The aim of this study is to establish a screening model to determine if bone scan should be performed for BM in Chinese patients at the time when PCa is diagnosed.

The study included 488 patients who were diagnosed with PCa between 2009 and 2011 at a single center. All patients received bone scans using technetium (99m)Tc methylene diphosphonate at the initial staging. If the bone scan finding was equivocal, computed tomography or magnetic resonance imaging was performed to confirm the diagnosis. Age, prostate-specific antigen (PSA) at diagnosis, clinical stage assigned according to the TNM 2002 staging system and biopsy Gleason score were collected in all patients. Multivariate logistic regression analysis was performed to identify statistically significant covariates and then receiver operating characteristic (ROC) curves were generated to identify optimal cut-off values. Using these cut-off values, a formula was devised to calculate an index value for BM screening at diagnosis. The model was cross-validated using the leave-one-out method.

Of the 488 patients, 65 patients (13.3%) had BM. The area under the ROC curve was 0.87 (95% confidence interval 0.83-0.94). The sensitivity of the cut-off point was 87.7% and the specificity was 73.1%. Bone scan is needed for all cT4 PCa patients, however, it is also advisable for cT1-T3 PCa patients who have a biopsy Gleason score ≤3 + 4 and a PSA >132.1, and for cT1-T3 patients having a Gleason score of ≥4 + 3 and PSA >44.5.

The regression model may help determine if bone scan is needed to detect BM from PCa at the time of diagnosis. The model was generated upon a single center experience. Further validation is needed in future studies.