Impact of Disease Burden on Cryoablation Prostate-specific Antigen Outcomes

Objectives

To identify prognostic factors for favorable biochemical outcome (prostate-specific antigen [PSA] <0.6 ng/mL) after primary whole gland prostate cryoablation.

Methods

The charts from 122 cryoablation patients treated at Cleveland Clinic from 2004 through May 2009 were reviewed. Patient age, race, PSA at diagnosis, Gleason score, risk category, prostate gland volume, clinical T stage, number of cores positive, percent of core involved with disease, ratios of number of cores positive to total cores biopsied and number of cores positive to prostate gland volume, and initial PSA results were studied. An initial post-cryoablation PSA of <0.6 was used as the criterion for favorable outcome based on previously published data.

Results

A total of 16.4% of patients had unfavorable postoperative PSA levels. On univariate analysis, number of cores positive (P = .031) and maximum percent core positive (P = .024) were prognostic of PSA outcome. On multivariate analysis, number of cores positive (P = .010), maximum percent core positive (P = .034), and ratio of number of positive cores to prostate gland volume (cm³) (P = .023) were prognostic for favorable PSA outcomes based on an initial PSA <.6 ng/mL.

Conclusions

Favorable PSA outcomes after primary prostate cryoablation appear to be correlated with disease burden. The relative disease burden as defined by the number of and percent core positive, and the ratio of number of cores positive to prostate gland volume (cm³) are highly prognostic for initial post-cryoablation PSA <0.6 ng/mL, which is associated with favorable long-term biochemical disease-free survival regardless of risk stratification.