Prospective Analysis of Outcomes in MRI Guided Prostate Cryoablations Using Novel Tools and Methods

Purpose: Prostate cancer is a major contributor to US cancer deaths {1}. MRI-guided interventions like cryoablation offer precise, minimally invasive therapies with favorable cancer control and low complication rates {2-4}. We will analyze the results to date from our institution’s nascent Interventional MRI Prostate Cryoablation program to evaluate the efficacy of the in-house tools and workflows developed to meet clinical needs.

Materials and Methods: Institutional review board approval was obtained for a prospective review. The study includes 19 patients currently who underwent MR-guided prostate cryoablation using a perineal grid and custom software developed since the program's 2022 inception, with follow-up from 3 to 12 months {5}. The mean patient age was 74 years (range: 61-83). Thirteen patients had recurrent prostate cancer, and 6 had primary prostate cancer. The average number of lesions was 1.21, with a mean size of 1.45 cm. Gleason scores were 3+3 (n=3), 3+4 (n=6), 4+3 (n=6), 4+4 (n=2), 4+5 (n=1), and 5+5 (n=1). Fourteen patients had focal ablation, and 5 had hemigland ablation. Pre-procedural PSA levels and follow-up levels at 3, 6, and 12 months were measured. Imaging included a 6-month PET or MRI and a 12-month PSMA PET scan to assess recurrence. Any immediate and/or long-term complications were recorded.

Results: On average, there was a 66.34% decrease in PSA levels comparing post- to pre-procedural levels, except for patient 1, who developed multifocal disease (Fig 1). 89% (17/19) of patients’ PSA follow-up values remained within the Phoenix criteria, with no biochemical recurrence. However, patients 3 and 4 showed new disease on their 12-month PSMA PET scan {6}. Six patients experienced mild adverse events (AEs) (frostbite (6), decreased sexual function (1,7), mild urinary leakage (4), small hematoma (18)), and one patient (4) had a moderate AE (bilateral pulmonary embolisms) {7}.

Conclusion: Our institution-specific software and perineal grid show promise in MR-guided cryoablations with few post-procedure AEs and favorable short-term outcomes. Larger studies are needed to assess long-term efficacy.