Accurate classification between non-clinically significant prostate cancer (non-csPCa) and clinically significant prostate cancer (csPCa) is essential for effective risk stratification and optimal management of prostate cancer. This study aimed to evaluate the consistency between preoperative and postoperative assessments of non-csPCa, and identify preoperative variables that can effectively predict the risk of csPCa. We analyzed data from 277 patients initially classified as non-csPCa after biopsy who underwent radical prostatectomy (RP) between August 2015 and January 2024. Univariate and multivariate logistic regression analyses were performed to identify predictors of csPCa. Receiver operating characteristic curves, calibration curves, and decision curve analyses were used to evaluate the performance of the nomogram model. Differences in biochemical recurrence rates between the non-csPCa group and csPCa group were analyzed using the log-rank test. Overall, 183 (66.1%) patients were reclassified as csPCa on the basis of postoperative pathology, with this group showing a higher incidence of biochemical recurrence versus non-csPCa (14 cases vs 0; P = 0.004). The following factors were independent predictors of csPCa: age, free prostate-specific antigen (fPSA)/total prostate-specific antigen (tPSA) ratio, cumulative cancer length, clinical tumor stage, and PSA density. In addition, a nomogram was developed with good predictive accuracy (area under the curve: 0.782). The substantial inconsistency between biopsy and RP pathology findings in the classification of non-csPCa highlights the limitations of biopsy-only management. The developed nomogram predicting the risk of csPCa provides urologists with a valuable tool for improved risk stratification and PCa management.

Keywords: biochemical recurrence; biopsy; clinically significant prostate cancer; Gleason score