Prognostic value of saturated prostate cryoablation for localized prostate cancer.

Abstract

To evaluate the oncological outcomes and complications of patients with saturated prostate cryoablation. A cohort of 208 patients cumulatively treated between June 2008 and December 2012 qualified for study inclusion, each undergoing total-gland cryoablation for prostate cancer. The degree of saturated prostate cryoablation was defined as the average prostate volume per cryoprobe (APVC), and divided into four groups (groups 1-4: <3 ml, 3 to <4 ml, 4 to <5 ml, ≧5 ml, respectively). Post-ablative complications were measured prospectively at weeks 1, 2, 4, 8, 12, and 24 by using the Common Terminology Criteria for Adverse Events. Biochemical failure was gauged by Phoenix criterion. The Kruskal-Wallis rank sum test and Chi-square test were used to compare clinical characteristics of therapeutic subsets. The Cox proportional hazard model was applied for comparison of recurrence risk between groups. APVC group 1 had the highest pre-operative PSA value and smallest prostate size among the groups. Multivariate analysis of risks of biochemical failures revealed that the larger the APVC, the higher the hazard (p for trend = 0.01). Compared to the group 1 patients, the hazard ratios of biochemical failures in groups 2-4 were 4.4 (confidence interval (CI): 0.5-37), 8.8 (CI 1.1-73), and 9.4 (CI 1.1-78), respectively. Nevertheless, the complication rate of APVC group 1 patients was similar to the other three groups. Saturated prostate cryoablation by reducing APVC would be beneficial for cancer control without compromising patient safety.