The Role of Multiparametric Magnetic Resonance Imaging in Focal Therapy for Prostate Cancer: A Delphi Consensus Project

BACKGROUND: Multiparametric Magnetic Resonance Imaging (mpMRI) of the prostate may have a role in detection of clinically significant prostate cancer in patients prior to, during and in the follow-up of focal therapy for prostate cancer. The lack of standardization and variations in technique and interpretation of images have contributed to debates about its reported performance characteristics. OBJECTIVE: To define the role of mpMRI for treatment planning -guidance and follow-up in focal therapy for prostate cancer based on a multidisciplinary Delphi consensus project. DESIGN SETTING AND PARTICIPANTS: An online consensus process based on a questionnaire was circulated according to the Delphi method. A face-to-face consensus meeting followed three rounds of questions that were sent to a 48 participant expert panel consisting of urologists, radiologists and engineers. Discussion points were identified by literature research and were sent to the panel by an online questionnaire in 3 rounds. Participants were presented with the results of the previous rounds. Conclusions formulated from the results of the questionnaire were discussed in the final face-to-face meeting. RESULTS: Consensus was reached in 41% of all key items. Patients selected for focal therapy should have biopsy proven PCa. Biopsies are ideally performed after mpMRI of the prostate. Standardization of imaging protocols is essential and mpMRIs have to be read by an experienced radiologist. In the follow-up after focal therapy, mpMRI should be performed after 6 months, followed by a yearly mpMRI. mpMRI findings should be confirmed by targeted biopsies before re-treatment. No consensus was reached about the question if mpMRI can replace transperineal template saturation biopsies for the exclusion of significant lesions outside the target lesion. CONCLUSIONS: Consensus was reached on a number of areas related to the conduct and interpretation and reporting of mpMRI for use in treatment planning, treatment guidance and follow-up of focal therapy for prostate cancer. Future studies, comparing mpMRI to transperineal saturation mapping biopsies, will confirm the important role of mpMRI in a variety of purposes in focal therapy for prostate cancer