MR guided focal laser ablation (FLA) is a thermal ablative technique that is now being used to treat T1a prostate cancer in a region-confined manner via coagulative necrosis. This phase 1 trial examines the safety and feasibility of transrectal MRI-guided FLA in men with intermediate-risk prostate cancer.
METHOD AND MATERIALSIn this HIPAA compliant, IRB-approved prospective single arm trial, the study cohort included eight men with multiparameteric MR (MP-MRI) detected, MR-US fusion biopsy proven, intermediate-risk, presumed stage T1a prostate cancer (Gleason 3+4 in all but one). treated with transrectal MR guided focal ablation. Secondary safety monitors (temperature probes) were inserted to assess the accuracy of MR thermometry. Follow-up MP-MRI and MR-US fusion biopsy was performed after six months.
RESULTSMR guided focal laser ablation was technically successful in all 8 subjects. No Clavian-Dindo adverse events > Grade 3 occurred, and no changes in IPSS (p=0.37), or IIEF-5 (p=0.76) were observed during 6 months of follow-up. Ablation zones, as measured by post-treatment contrast enhanced MP-MRI, had a median volume of 3 cc or 7.7% of prostate volume. A significant drop in serum PSA level was observed in 7/8 men after six months (p<0.01). An average of 15 cores were taken during follow-up 6 monht MR-US fusion bx, in which no ablation zone cancer was detected in 5/8 men (62.5%).
CONCLUSIONTransrectal MR guided focal laser ablation of the prostate is feasible and safe in men with intermediate-grade, stage 1a prostate cancer without serious adverse events or changes in urinary or sexual function. Comprehensive MR-US gudied fusion biopsy follow-up indicates that larger margins than previously thought may be necessary for effective focal therapy.
CLINICAL RELEVANCE/APPLICATIONTransrectal MR guided focal laser ablation (FLA) may offer a safe and effective minimally invasive therapy for a small minority of patients with T1a intermediate risk prostate cancer as demonstrated in this pilot T1a trial.