Presented by: David Margel MD, PhD, MBA
Raphael Hospital

Introduction

Active surveillance is an accepted treatment for low-risk prostate cancer, but still between 30-50% of patients need treatment. Prostate MRI is an integral part of a patient's evaluation before a prostate biopsy. The purpose of this study was to check whether there is a difference in the risk of progression depending on  initial MRI findings.

Materials

In this study, we included men who were diagnosed with low-risk prostate cancer in an initial fusion biopsy. All men included  chose active surveillance and performed atleast one more fusion biopsy during  follow-up. We only included patients whose prostate cancer was sampled in the  index lesion of the initial MRI. We divided the patients according to the severity of the PIRADS score in the INDEX LESION performed prior to the first biopsy.

The primary study outcome was disease progression ( to GG2 or higher) during active suivailance in the index lesion.

We performed univariate and multivariate analyses to predict progression and in addition we performed several sensitivity analyzes to confirm the findings.

Results

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203 patients were included in the study (PIRADS 3= 69; PIRADS 4= 94; PIRADS 5= 40) At a median follow-up of 30 months, disease progression was observed in 52% of patients. Of these, 22% of patients with PIRADS 3 (n=15); 65% of patients with PIRADS 4 (n=61); and for 75% of the patients with PIRADS 5 (n=29).

On multivariable analysis, PIRADS score was an independent predictor for disease progression (PIRADS4 and above HR 3.3 95%CI 2.1-3.9).

On multiple sensitivity analyses, the association of progression to initial PIRADS score remained strong even after controlling for initial PSA level, the size of the prostate, the location of the lesion, the identity of the biopsy operator/pathologist or radiologist and the time between biopsies.

Conclusion

Among men with low-risk prostate cancer  a PIRADS grade of 4 or higher on MRI is associated with a high risk of progression. It is unclear whether this is reclassification or true biological progression.

Funding

none

Lead Authors

Yaara Ber, PhD
Raphael Hospital