Purpose: We evaluated 5-year oncologic and functional outcomes of hemigland cryoablation of localized prostate cancer.
Materials and methods: We reviewed the records of 160 consecutive men who underwent hemigland cryoablation of localized prostate cancer. Recurrent and/or residual clinically significant prostate cancer was defined as Grade Group 2 or greater on followup biopsy. A prostate specific antigen nadir plus 2 ng/ml according to the Phoenix criteria was used to define biochemical failure. Radical treatment was defined as any whole gland therapy. Treatment failure was defined as any radical and/or whole gland treatment, systemic therapy initiation, metastasis or prostate cancer specific mortality. The study primary end point was treatment failure-free survival. The secondary end points were survival free of biochemical failure, clinically significant prostate cancer and radical treatment. Followup biopsy and functional outcomes were also evaluated. Statistical analysis included the Kaplan-Meier method, and univariate and multivariable Cox and logistic regression with significance considered at p <0.05.
Results: Median patient age was 67 years, baseline prostate specific antigen was 6.3 ng/ml and followup was 40 months. A total of 131 patients (82%) had D'Amico intermediate (66%) or high risk (16%) prostate cancer. At 5 years the treatment failure-free survival rate was 85%, the biochemical failure-free survival rate was 62% and the survival rate free of clinically significant prostate cancer was 89%. Higher baseline prostate specific antigen independently predicted treatment failure (p <0.001), biochemical failure (p=0.048), recurrence and radical treatment (p <0.01). Grade Group 3 or greater independently predicted treatment failure (p=0.04). The metastasis-free survival rate was 100% at 5 years. Pad-free continence and potency (erections sufficient for intercourse) were retained in 97% and 73% of patients, respectively. There was no rectal fistula or mortality.
Conclusions: Hemigland cryoablation of localized prostate cancer provides effective midterm oncologic outcomes with good continence and potency. Patients with higher baseline prostate specific antigen are at increased risk for biochemical failure, recurrent cancer and treatment failure.
Keywords: cryosurgery; prostate specific antigen; prostatic neoplasms; risk; treatment failure.