Propensity Score-Matched Comparison of Partial to Whole-Gland Cryotherapy for Intermediate-Risk Prostate Cancer: An Analysis of the Cryo On-Line Data Registry Data

Objective: To compare the oncologic and functional outcomes of partial vs whole-gland cryotherapy for men with intermediate-risk prostate cancer.

Subjects/patients: Men with intermediate-risk prostate cancer treated with primary prostate cryotherapy from 1993 to 2013 were selected from the Cryo On-Line Data Registry for a 1:1 matched comparison between those undergoing whole-gland and partial prostate cryotherapy (targeted ablation, unilateral/bilateral nerve-sparing ablations). A propensity score was developed based on age, prebiopsy serum prostate-specific antigen, biopsy Gleason score, clinical stage, prostate volume, neoadjuvant androgen deprivation status, year of surgery, and pretreatment potency. Outcomes were biochemical progression-free survival (BPFS) using the American Society for Therapeutic Radiation Oncology (ASTRO) and Phoenix criteria, 12-month continence (strictly pad free), and sexual function (potency sufficient for sexual intercourse). After propensity score matching, BPFS was compared using Kaplan-Meier analysis and functional outcomes using chi-square tests.

Results: In all, 897 men were identified (731 whole gland and 166 partial). Postmatching, 166 pairs of men were analyzed (mean follow-up 31 months). The 2/5-year BPFS rate was 87.2%/76.4% for whole-gland vs 80.7%/70.0% for partial ablation using Phoenix (p = 0.26) and 72.3%/69.6% for whole-gland vs 82.1%/75.0% for partial ablation using ASTRO criteria (p = 0.10). Of 164 pairs, the 12-month continence rate was similar, 94.1% vs 95.1% (p = 0.803). Of 139 pairs, the 12-month rate of effective intercourse was 29.5% for whole-gland and 46.8% for partial ablation (odds ratio 2.1, p = 0.003). The incidence of post-treatment urinary retention was 6.0% and 6.6% (p = 0.88) following whole-gland and partial ablation, respectively, and that of rectourethral fistula was 1.2% and 0% (p = 0.50).

Conclusion: Partial ablation results in better post-treatment sexual function compared with whole-gland ablation in men with intermediate-risk prostate cancer. We did not observe a difference in early BPFS between the two groups.