Radiation Therapy and Irreversible Electroporation for Intermediate Risk Prostate Cancer (RTIRE)

TPS403 Background: The objective of the RTIRE clinical trial (NCT05345444) is to demonstrate the feasibility, safety, and early oncologic efficacy of combining MRI-guided stereotactic body radiation therapy (MRgSBRT) with irreversible electroporation (IRE) for men with intermediate-risk localized prostate cancer. Methods: Inclusion criteria: 1) Men aged ≥18, 2) ECOG 0 –1, 3) Histologically confirmed intermediate risk prostate cancer per NCCN guidelines, 4) Focal grade group 2 (GG2) or 3 (GG3) cancer in multi-parametric magnetic resonance imaging (mpMRI) target, 5) Gland size < 80cc, 6) Ability to undergo IRE, 7) Ability to receive MRI-guided SBRT, 8) Ability to complete the HRQOL assessment surveys, 9) Willingness to undergo 12 month follow up biopsy. Exclusion criteria: 1) Prior TURP, 2) Prior history of focal therapy, 3) Prior history of receiving pelvic radiotherapy, 4) Patient with history of inflammatory bowel disease, 5) History of bladder neck or urethral stricture. Study Design/Endpoints: This is a feasibility and safety study assessing the ability to perform IRE followed by real-time MRgSBRT. Subjects will undergo focal IRE followed by MRgSBRT (>6 weeks after IRE) to the prostate +/- seminal vesicles prescribed to 32.5 Gy in 5 fractions. The primary endpoint of the first portion of the trial is feasibility, defined as at least 80% of subjects (8 of 10 subjects) undergoing assessment at 12-weeks post-IRE and at 6-weeks post-MRgSBRT within 1 year from enrollment of the first subject. The expansion phase will include an additional 40 subjects to assess side effect profile and early oncologic efficacy (n=50) at 12 months post RTIRE. RTIRE has enrolled 8 subjects in 3 months and will proceed to the expansion phase. Secondary endpoints include: 1) short-term safety as measured by treatment-related adverse events, 2) oncologic efficacy as measured by number of subjects with presence of ≥GG2 cancer at 12 months post-RTIRE therapy, 3) health-related quality of life (HRQOL) as measured by Expanded Prostate Cancer Index Composite for Clinical Practice (EPIC-CP), International Prostate Symptom Score (IPSS), International Index of Erectile Function (IIEF-5) 4) post-RTIRE prostate-specific antigen (PSA) kinetics including time to PSA nadir and post-nadir PSA stability, 5) assessment of pre and post-RTIRE mpMRI changes to evaluate the area of necrosis and presence of residual tissue, 6) rates of biochemical and clinical progression and the need for secondary or adjuvant treatment following RTIRE. Clinical trial information: NCT05345444 .