Medium Term Outcomes of Focal Cryoablation for Intermediate and High Risk Prostate Cancer: MRI and PSA are Not Predictive of Residual or Recurrent Disease

Abstract

To understand oncologic outcomes of focal cryoablation for prostate cancer and efficacy MRI and PSA to predict residual disease and recurrence. We retrospectively analyzed patients who underwent focal cryotherapy at a single institution. Inclusion criteria included clinically localized biopsy-proven cancer that was clearly visible on MRI or ultrasound. The primary outcomes were failure-free survival (FFS) defined as no transition to radical, whole-gland or systemic therapy and biochemical recurrence (Phoenix PSA nadir +2 increases), and secondary outcomes included changes in the Gleason grade group (GG) and MRI findings. 75 patients completed post cryotherapy biopsy with a median follow-up of 1.89 [IQR 1.19-2.77] years. Failure free survival was met by 96.2% of patients at 2 year follow up and of those who did not meet this outcome, 3 had metastasis, 1 had a salvage prostatectomy and 5 underwent radiation. On the treated side of the prostate, 7 (9.5%) of patients had residual ≥GG2 disease compared to 7 (9.5%) patients on the untreated side. Out of the 12 patients who had residual ≥GG2 disease at follow up biopsy (either on treated or untreated side of the prostate), 11 (91.7%) had PI-RADS 1-3 on follow up MRI. Using a multivariate cox proportional hazards model, Phoenix criteria for recurrence (PSA nadir +2) was not predictive for FFS. Focal cryotherapy is effective for treating focal lesions of prostate cancer, but patients require continued surveillance. MRI and PSA are not reflective of residual disease on follow up biopsy.