Prostate Specific Antigen Nadir of 0.1 or Less Is a Predictor of Treatment Success in Men Undergoing Salvage Whole Prostate Gland Cryoablation

Abstract

Purpose: To assess factors that affect prostate biopsy results following salvage whole gland cryoablation.

Patients and methods: One hundred seventy-four patients underwent prostate biopsy following salvage whole gland cryoablation of the prostate in the Cryo-OnLine Database registry. Wilcoxon rank-sum and χ² tests and logistic regression analysis were used to assess predictors of positive biopsy. Prostate specific antigen (PSA) nadir was divided into a statistical tertile for comparisons between different nadir PSA cut points.

Results: Fifty-two of 174 (29.9%) of this highly select group of men who underwent biopsy had a posttreatment biopsy demonstrating malignant cancer. Men who had positive biopsy following salvage therapy had significantly higher median nadir PSA, shorter median time to prostate biopsy, and shorter median time to biochemical failure. Compared to the lowest tertile (PSA nadir defined as ≤0.1 ng/mL), PSA in the second tertile (0.11-0.8 ng/mL) and third tertile (>0.8 ng/mL) demonstrated increased odds ratio (OR) for positive biopsy, 4.34 (95% confidence interval [CI] 1.66, 11.4, p = 0.003) and 2.81 (95% CI 1.14, 7.00, p = 0.02), respectively, in adjusted models. In addition, men with a presalvage PSA >20 (OR 7.65; 95% CI 2.03, 28.9; p = 0.003) and Gleason score ≥8 (OR 2.26; 95% CI 0.93, 5.47; p = 0.07) had a higher OR of positive biopsy.

Conclusions: Nadir PSA of 0.1 ng/mL or less following salvage cryotherapy is predictive of treatment success. Routine biopsy should be reserved for men with nadir PSA >0.1 ng/mL and patients with high risk features of prostate cancer before salvage cryoablation.

Keywords: cryoablation; prostate cancer; salvage therapy.