Combined multiple clinical characteristics for prediction of discordance in grade and stage in prostate cancer patients undergoing systematic biopsy and radical prostatectomy

Abstract

Background: The present study aimed to develop three nomograms by incorporating multiple clinical characteristics to identify those prostate cancer (PCa) patients with high probability of incorrect biopsy Gleason grade group (GG) before making treatment decisions.

Methods: We retrospectively collected data from PCa patients who underwent systematic biopsy and radical prostatectomy from January 2015 to December 2019 at Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology. Univariable and multivariable logistic regression analyses were preformed to identify independent risk factors associated with upgrading, upstaging and downgrading. By incorporating selected clinical parameters with high predictive value, we constructed three nomograms to predict the probability of upgrading, upstaging and downgrading. Discrimination of nomograms was evaluated by receiver operating characteristic (ROC) analysis with corresponding area under the curve (AUC). Decision curve analysis (DCA) and calibration curves were performed to evaluate calibration and the clinical usefulness of nomograms. Performance of the three nomograms was validated in the testing dataset.

Results: There were 585 PCa patients in total enrolled in this study who met the inclusion criteria. Of the 585 patients, the disease of 262 (44.8 %) was upgraded and 68 (11.6 %) was downgraded, and the disease of 67 (11.5 %) was upstaged. With regard to findings of multivariable analyses, patients' age and biopsy GG (GG 2, GG 3, GG 4 versus GG 1) were significantly associated with upgrading. Moreover, maximum diameter of the index lesion (D-max), clinical T stage (cT3a, cT3b versus cT1-2), number of positive cores and total tumor length were significantly associated with upstaging. Furthermore, d-max, %fPSA (> 0.16 versus ≤ 0.16) and biopsy GG (GG 3, GG 4, GG 5 versus GG 2) were independent predictors of downgrading. The three nomograms displayed good calibration in respective calibration plots. ROC analyses showed good discrimination with satisfactory AUC values and DCA plots demonstrated that the upgrading-risk nomogram, upstaging-risk nomogram and downgrading-risk nomogram were all clinically useful.

Conclusions: The upgrading-risk nomogram, upstaging-risk nomogram, and downgrading-risk nomogram were developed and correctly predicted the probability of incorrect Gleason grade group assigned to patients undergoing systematic biopsy.

Keywords: Biopsy; Downgrading; Gleason grade group; Prostate cancer; Upgrading; Upstaging.