Login to Access Video or Poster Abstract: MP70-01
Sources of Funding: This research was made possible through the NIH Medical Research Scholars Program, a public-private partnership supported jointly by the NIH and generous contributions to the Foundation for the NIH by the Doris Duke Charitable Foundation (Grant #2014194), the American Association for Dental Research, the Colgate-Palmolive Company, Genentech, and other private donors. For a complete list, visit the foundation website at http://www.fnih.org.

Introduction

Intermediate risk prostate cancer (IRPCa, Gleason 7 with PSA<20) patients often receive whole gland therapy, potentially exposing them to overtreatment and side effects associated with treatment. Focal therapy (FT) minimizes these risks while treating all clinically significant cancer. We aimed to determine the accuracy of multiparametric MRI (mpMRI) and fusion biopsy (Fbx) in selecting candidates for FT.

Methods

Clinical and pathology data was prospectively collected from IRPCa patients who underwent prostate MpMRI prior to radical prostatectomy (RP) (2010-16). Patients were analyzed in two cohorts: those who received mpMRI with Systematic Biopsy (Sbx) alone and those who received combination mpMRI Fbx/Sbx. Patients were considered suitable for FT if they had IRPCa in only one lobe of the prostate with a corresponding mpMRI visible lesion on the same side. Poor candidates were patients found to have high risk cancer (Gleason 8-10), IRPCa bilaterally, or PCa lesions that crossed the midline. Good candidates were confirmed with whole mount pathology analysis performed.

Results

185 patients with IRPCA (median age of 61 (IQR 10) years and PSA 5.67 (IQR 4.5 ng/dl) were included in the study. 129 (69.7%) had MRI and combination Fbx/Sbx. There was no difference in age, PSA and race distribution between the two cohorts. 98 (53.0%) patients were considered good FT candidates based on preoperative MpMRI and biopsy findings. Whole mount pathology analysis confirmed 67.1% of FT candidates determined from pre RP information (31.9% of total IRPCa patients). A higher proportion of FT candidates determined by mpMRI and Fbx/Sbx was confirmed on whole mount than FT candidates determined by mpMRI and Sbx alone (73.8% vs 44.4%; p=0.026). Failure on whole mount was due to Gleason upgrade in 25.0% of patients and due to presence of bilateral IRPCa in the rest. On regression analysis, low PSA was the sole predictor of confirmed FT candidates on final pathology (p=0.021).

Conclusions

MpMRI Fbx/Sbx is a more accurate tool than mpMRI with Sbx alone for predicting FT candidates. However, the application of mpMRI and Fbx/Sbx criteria to predict FT candidates may result in undertreatment of approximately one quarter of the patients with significant cancer. More accurate predictive capability is needed before FT can be offered to all patients with IRPCa.

Funding

This research was made possible through the NIH Medical Research Scholars Program, a public-private partnership supported jointly by the NIH and generous contributions to the Foundation for the NIH by the Doris Duke Charitable Foundation (Grant #2014194), the American Association for Dental Research, the Colgate-Palmolive Company, Genentech, and other private donors. For a complete list, visit the foundation website at http://www.fnih.org.