Matthijs J Scheltema1, John I Chang2, Willemien van den Bos2, Maret Böhm3, Warick Delprado4, Ilan Gielchinsky2, Theo M de Reijke5, Jean J de la Rosette5, Amila R Siriwardana2, Ron Shnier6, Phillip D Stricker7. 1. Garvan Institute of Medical Research & The Kinghorn Cancer Centre, Darlinghurst, Sydney, NSW, Australia; St. Vincent's Prostate Cancer Centre, Department of Urology, Darlinghurst, Sydney, NSW, Australia; Academic Medical Center, Department of Urology, University of Amsterdam, The Netherlands. Electronic address: m.scheltema@garvan.org.au. 2. Garvan Institute of Medical Research & The Kinghorn Cancer Centre, Darlinghurst, Sydney, NSW, Australia; St. Vincent's Prostate Cancer Centre, Department of Urology, Darlinghurst, Sydney, NSW, Australia. 3. Garvan Institute of Medical Research & The Kinghorn Cancer Centre, Darlinghurst, Sydney, NSW, Australia. 4. University of Notre Dame, Sydney, NSW, Australia. 5. Academic Medical Center, Department of Urology, University of Amsterdam, The Netherlands. 6. Southern Radiology, Randwick, Sydney, NSW, Australia. 7. St. Vincent's Prostate Cancer Centre, Department of Urology, Darlinghurst, Sydney, NSW, Australia.
Abstract
BACKGROUND: It is recommended to perform multiparametric magnetic resonance imaging (mpMRI) in the follow-up following focal therapy of prostate cancer (PCa). OBJECTIVE: To determine the diagnostic accuracy of mpMRI to detect residual PCa following focal therapy with irreversible electroporation. DESIGN, SETTING, AND PARTICIPANTS: Seventy-six patients with biopsy-proven localized PCa consented for primary irreversible electroporation between February 2013 and March 2016. Final analysis was performed on 50 patients that received follow-up mpMRI at 6 mo, serial prostate-specific antigen (PSA) testing, and transperineal template-mapping biopsies at 12 mo. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Outfield regions of interest (ROI) were reported using PI-RADS version 2. A binary outcome (suspicious vs nonsuspicious) was given for the infield ablation zone. Sensitivity, specificity, positive predictive values, and negative predictive values were calculated for different definitions of significant PCa: (1) Gleason ≥4+3 or Gleason ≥3+3 with a maximum cancer core length ≥6mm, (2) Gleason ≥3+4 or Gleason ≥3+3 with a maximum cancer core length ≥4mm, for outfield and infield ROI. Multivariate linear regression analyses evaluated the additional value of nadir PSA. RESULTS AND LIMITATIONS: Sensitivity, specificity, positive predictive values, and negative predictive values of infield ROI was 43%, 86%, 33%, and 90% for definition 1 and 38%, 86%, 33%, and 88% for definition 2, respectively. For outfield ROI this was 33%, 82%, 20%, and 90% for definition 1 and 38%, 86%, 50%, and 80% for definition 2. PSA had no additional value in predicting residual significant PCa. Limitations include retrospective design, single reader, and low incidence of residual PCa. CONCLUSIONS: Our preliminary data suggest that mpMRI can rule out high-volume residual PCa. However, follow-up biopsies should still be performed to determine oncological control. PATIENT SUMMARY: Multiparametric magnetic resonance imaging is able to detect high-volume significant prostate cancer following focal therapy. Prostate biopsies are still required in the follow-up of focal therapy as (low-volume) significant prostate cancer is being missed by multiparametric magnetic resonance imaging.
BACKGROUND: It is recommended to perform multiparametric magnetic resonance imaging (mpMRI) in the follow-up following focal therapy of prostate cancer (PCa). OBJECTIVE: To determine the diagnostic accuracy of mpMRI to detect residual PCa following focal therapy with irreversible electroporation. DESIGN, SETTING, AND PARTICIPANTS: Seventy-six patients with biopsy-proven localized PCa consented for primary irreversible electroporation between February 2013 and March 2016. Final analysis was performed on 50 patients that received follow-up mpMRI at 6 mo, serial prostate-specific antigen (PSA) testing, and transperineal template-mapping biopsies at 12 mo. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Outfield regions of interest (ROI) were reported using PI-RADS version 2. A binary outcome (suspicious vs nonsuspicious) was given for the infield ablation zone. Sensitivity, specificity, positive predictive values, and negative predictive values were calculated for different definitions of significant PCa: (1) Gleason ≥4+3 or Gleason ≥3+3 with a maximum cancer core length ≥6mm, (2) Gleason ≥3+4 or Gleason ≥3+3 with a maximum cancer core length ≥4mm, for outfield and infield ROI. Multivariate linear regression analyses evaluated the additional value of nadir PSA. RESULTS AND LIMITATIONS: Sensitivity, specificity, positive predictive values, and negative predictive values of infield ROI was 43%, 86%, 33%, and 90% for definition 1 and 38%, 86%, 33%, and 88% for definition 2, respectively. For outfield ROI this was 33%, 82%, 20%, and 90% for definition 1 and 38%, 86%, 50%, and 80% for definition 2. PSA had no additional value in predicting residual significant PCa. Limitations include retrospective design, single reader, and low incidence of residual PCa. CONCLUSIONS: Our preliminary data suggest that mpMRI can rule out high-volume residual PCa. However, follow-up biopsies should still be performed to determine oncological control. PATIENT SUMMARY: Multiparametric magnetic resonance imaging is able to detect high-volume significant prostate cancer following focal therapy. Prostate biopsies are still required in the follow-up of focal therapy as (low-volume) significant prostate cancer is being missed by multiparametric magnetic resonance imaging.