Predicting the probability of significant prostate cancer in Japanese men with serum prostate-specific antigen less than 10 ng/mL: development of a novel pre-biopsy nomogram.

Objectives: To develop and assess a new nomogram incorporating pre-biopsy clinical data to predict significant prostate cancer in Japanese men with a serum prostate-specific antigen (PSA) level of less than 10 ng/mL.

Methods: We collected pre-biopsy data from 620 men with a serum total PSA of less than 10 ng/mL. They included 491 men with a negative biopsy and 129 men who were confirmed to have histological prostate cancer and subsequently underwent radical prostatectomy. Clinically significant tumors were defined as those with a tumor volume larger than 0.5 mL and/or a Gleason score of 7 or more.

Results: One hundred and seven prostatectomy patients had clinically significant cancers. Stepwise multivariate logistic regression analysis showed that digital rectal examination findings, PSA adjusted for transition zone volume and free-to-total PSA ratio were the significant independent predictors of significant cancers (P < 0.0001). Using these pre-biopsy independent factors, a nomogram was developed to predict significant cancers. According to a receiver operating characteristics analysis, the nomogram showed an area under the curve of 0.831.

Conclusion: This represents the first nomogram to predict the probability of clinically significant cancers before biopsy. This tool is most likely to be useful in the management of patients with moderate to elevated PSA.