Early-Medium-Term Outcomes of Primary Focal Cryotherapy to Treat Nonmetastatic Clinically Significant Prostate Cancer from a Prospective Multicentre Registry

Abstract

Background: Focal cryotherapy can be used to treat patients with clinically significant nonmetastatic prostate cancer to reduce side effects.

Objective: Early-medium-term cancer control and functional outcomes.

Design, setting, and participants: A prospective registry-based case series of 122 consecutive patients undergoing focal cryotherapy between October 1, 2013, and November 30, 2016, in five UK centres. Median follow-up was 27.8mo [interquartile range (IQR) 19.5-36.7]. A total of 35 patients (28.7%) had National Comprehensive Cancer Network (NCCN) high risk and 87 (71.3%) had intermediate risk disease. Risk and zonal stratification included multiparametric magnetic resonance imaging (mpMRI) with targeted and systematic biopsies, or transperineal mapping biopsies.

Intervention: Focal cryoablation of MR-visible tumours.

Outcome measurements and statistical analysis: Follow-up involved prostate-specific antigen (PSA) monitoring, mpMRI, and for-cause biopsies. Primary outcome was failure-free survival (FFS), defined as transition to radical, whole-gland, or systemic therapy, or metastases/death. Secondary outcomes included adverse events and functional outcomes.

Results and limitations: A total of 80 (65.6%) had anterior ablation, 23 (19.7%) combined posterior and anterior ablation, and two (1.6%) posterior ablation alone (SeedNet or Visual-ICE, BTG plc). Median age was 68.7yr (IQR 64.9-73.8) and preoperative PSA 10.8ng/ml (IQR 7.8-15.6). Overall FFS at 3yr was 90.5% [95% confidence interval (CI) 84.2-97.3]. When stratified for the NCCN risk group, 3-yr outcomes were 84.7% (95% CI 71.4-100) in high risk and 93.3% (95% CI 86.8-100) in intermediate risk. At last follow-up, incontinence defined as any pad use was 0/69 (0%) and erectile dysfunction (defined as erections insufficient for penetration) was 5/31 (16.1%). Limitations include lack of long-term outcomes.

Conclusions: Focal cryotherapy primarily for anterior intermediate and high-risk prostate cancer results in good rates of cancer control and low rates of treatment-related side effects.

Patient summary: In this multicentre study of 122 patients undergoing focal cryotherapy for medium- to high-risk prostate cancer, at 3yr, no patient died from their cancer whilst failure-free survival, was approximately 90%. None of the patients needed pads for managing urine leakage, although 16% had erection problems.

Keywords: Clinically significant prostate cancer; Cryotherapy; Focal therapy.