Low-Risk Prostate Cancer and Tumor Upgrading in the Surgical Specimen: Analysis of Clinical Factors Predicting Tumor Upgrading in a Contemporary Series of Patients Who were Evaluated According to the Modified Gleason Score Grading System

Abstract

Objective: To identify significant clinical factors associated with prostate cancer (PCa) upgrading the low-risk PCa patients graded according to the modified Gleason score system. Materials and Methods: The logistic regression model was used to evaluate the records of 438 patients. Results: There were 170 cases (38.8%) of low-risk PCa and tumors were upgraded in 111 patients (65.3%). Only prostate specific antigen (PSA) and the proportion of positive cores (P+) were independent predictors of tumor upgrading. Further exploration was investigated by categorizing and regressing PSA (≤ 5.0 vs. > 5.0 ng/ml) and P+ (≤ 0.20 vs. > 0.20). The odds ratio of PSA > 5 ng/ml was 1.32 and of P+ > 0.20 was 2.71. The population was stratified into very low-risk with PSA ≤ 5 ng/ml and P+ ≤ 0.20 (class A), low-risk with PSA > 5 ng/ml and P+ ≤ 0.20 (class B), intermediate risk with PSA ≤ 5 ng/ml and P+ > 0.20 (class C), and high risk with PSA > 5 ng/ml and P+ 0.20 (class D). Upgrading rates were extremely low in class A (9%), extremely high in D (50.5%), and moderate (20%) in B and C. Conclusion: Patients diagnosed with low-risk PCa at biopsy are a heterogeneous population because they include subsets with undetected high-grade disease. Significant clinical predictors of upgrading include the PSA value and P+. In low-risk PCa, we identified a high-risk upgrading subgroup that needed repeat biopsies in order to reclassify the tumor grade and to reassess the clinical risk category.