Nomogram for prediction of prostate cancer with serum prostate specific antigen less than 10 ng/mL

Although prostate-specific antigen (PSA) is a very useful screening tool, prostate biopsy is still necessary to confirm prostate cancer (PCA). However, it is reported that PSA is associated with a high false-positive rate and prostate biopsy also has various procedure-related complications. Therefore, the authors have devised a nomogram, which can be used to estimate the risk of PCA, using available clinical data for men with a serum PSA less than 10 ng/mL. Prostate biopsies were obtained from 2,139 patients from January 1998 to March 2011. Of them, 1,171 patients with a serum PSA less than 10 ng/mL were only included in this study. Patient age, PSA, free PSA, prostate volume, PSA density and percent free PSA ratio were analyzed. Among 1,171 patients, 255 patients (21.8%) were diagnosed as PCA. Multivariate analyses showed that patient age, prostate volume, PSA and percent free PSA had statistically significant relationships with PCA (P < 0.05) and were used as nomogram predictor variables. The area under the (ROC) curve for all factors in a model predicting PCA was 0.759 (95% CI, 0.716-0.803).