Five-year Oncologic Outcomes Following Primary Partial Gland Cryo-ablation Prospective Cohort Study of Men With Intermediate-risk Prostate Cancer.

OBJECTIVE

To assess 5-year oncologic outcomes following primary partial gland cryo-ablation (PPGCA) in intermediate-risk prostate cancer.

METHODS

Of 476 men undergoing PPGCA enrolled in our prospective oncologic and functional outcomes study, 313 had magnetic resonance imaging (MRI) concordant intermediate-risk prostate cancer with no out-of-field Gleason grade group ≥2, gross extracapsular extension, or extreme apical disease on pre-treatment multi-parametric MRI. Prostatic-specific antigen was monitored every 6 months, and multi-parametric MRI at 6 to 12, 24, 42, and 60 months. Protocol biopsies at 6-12 months and 24 months were discontinued after interim analysis showing low rates of clinically significant prostate cancer (csPCa) defined as any Gleason grade group ≥2 disease. Freedom-from-failure was defined as no prostate cancer-specific mortality, metastatic disease, or whole-gland salvage treatment.

RESULTS

csPCa was detected in 33 (10.5%) subjects. Ninety-one had ≥4.5 years of follow-up data with a mean of 8.9, 3.4, and 2.0 surveillance prostatic-specific antigen tests, MRIs, and prostate biopsies; none were lost to follow-up. At 5 years, rates of freedom-from-recurrence of in-field, out-of-field, and overall csPCa were 86% (95% confidence interval [CI]: 78-96), 85% (95% CI: 63-94), and 70% (95% CI: 57-84). The proportion with freedom-from-failure at 5 years was 89% (95% CI: 83-95). None died from prostate cancer, 1 (1%) developed metastasis, 15 (16.5%) underwent whole-gland salvage treatment, and 15 (16.5%) underwent salvage focal therapy. Only 3 of 91 (3.3%) eligible men were non-compliant with 5-year surveillance protocol.

CONCLUSION

Very encouraging intermediate-term oncological outcomes following PPGCA were observed with very high compliance to a rigorous prospective protocol for identifying recurrent csPCa.