How does a prebiopsy mri approach for prostate cancer diagnosis affect prostatectomy upgrade rates?

Pathological Assessment of Men with Grade Group 2 Prostate Cancer

PURPOSE

A variety of treatment options are now available for men with localized prostate cancer (PC); however, there is still debate in determining how and when to intervene for Grade Group (GG) 2 disease. Our study aims to formulate strategies to identify men at risk of upgrading and having adverse pathological outcomes.

MATERIALS AND METHODS

This retrospective study includes 243 patients with GG2 PC that were treated with radical prostatectomy between 2015 and 2021. Patients on active surveillance, previous history of prostate biopsy, hormonal and/or radiation therapy prior to surgery were excluded from this study. A retrospective analysis was conducted using clinicopathological data obtained from medical records.

RESULTS

Prostate-specific antigen (PSA) and Prostate Imaging Reporting and Data System (PI-RADS) score were statistically significant variables for risk of upgrading. In men who had presence of composite poor outcomes, PSA, PI-RADS score, presence of extraprostatic extension and seminal vesical invasion on MRI, number of positive cores, percentage of high grade (pattern 4/5) on prostate biopsy and Gleason pattern 4 volume on biopsy were all statistically significant variables. Strategy 8 (PI-RADS 5 lesion or percentage high grade [Gleason pattern 4] on prostate biopsy grade >10% or >3 cores positive on prostate biopsy) had significant association to identifying the highest number of men with upgrading and composite poor outcomes.

CONCLUSIONS

Our study supports the use of strategy 8 in treatment decision making of men with GG2 PC. Further validation of the use of this strategy is warranted.

Reliability of Systematic and Targeted Biopsies versus Prostatectomy

Systematic Biopsy (SBx) has been and continues to be the standard staple for detecting prostate cancer. The more expensive MRI guided biopsy (MRITBx) is a better way of detecting cancer. The prostatectomy can provide an accurate condition of the prostate. The goal is to assess how reliable SBx and MRITBx are vis à vis prostatectomy. Graded Gleason scores are used for comparison. Cohen's Kappa index and logistic regression after binarization of the graded Gleason scores are some of the methods used to achieve our goals. Machine learning methods, such as classification trees, are employed to improve predictability clinically. The Cohen's Kappa index is 0.31 for SBx versus prostatectomy, which means a fair agreement. The index is 0.34 for MRITBx versus prostatectomy, which again means a fair agreement. A direct comparison of SBx versus prostatectomy via binarized graded scores gives sensitivity 0.83 and specificity 0.50. On the other hand, a direct comparison of MRITBx versus prostatectomy gives sensitivity 0.78 and specificity 0.67, putting MRITBx on a higher level of accuracy. The SBx and MRITBx do not yet match the findings of prostatectomy completely, but they are useful. We have developed new biomarkers, considering other pieces of information from the patients, to improve the accuracy of SBx and MRITBx. From a clinical point of view, we provide a prediction model for prostatectomy Gleason grades using classification tree methodology.