Hemigland Cryoablation of Clinically Significant Prostate Cancer: Intermediate-Term Followup via Magnetic Resonance Imaging Guided Biopsy

Abstract

Purpose: Contemporary biopsy methods were used to determine the success rate of hemigland cryoablation as a primary treatment for prostate cancer. Previous studies, often including men at low risk, have used magnetic resonance imaging guided biopsy to a variable extent. Here, we uniformly used the new diagnostic modality to study all men, each with clinically significant cancer, at baseline and at short and intermediate-term followup.

Materials and methods: In an open label trial (NCT03503643) 61 men with unilateral cancer (all clinically significant, ie Grade Group 2 or greater) underwent primary hemigland cryoablation. Subjects were 80% Caucasian, average age 69 years, prostate specific antigen 6.6 ng/ml and prostate volume 38 cc. Biopsy was performed using magnetic resonance imaging/ultrasound fusion prior to treatment and at the followup intervals of near-term (6 months, in 61) and intermediate-term (18 months, in 27). All utilities of fusion biopsy, ie targeting of magnetic resonance imaging visible lesions, template systematic sampling, and in followup, tracking of prior positive sites, were used throughout the study to detect clinically significant cancer, the primary end point.

Results: Following treatment 82% of men (50 of 61) had no biopsy detectable clinically significant prostate cancer at 6-month near-term followup and 82% of men (22 of 27) reaching the 18-month intermediate-term remained biopsy negative. Combination of the 3 sampling methods provided maximal cancer detection. During followup a new focus of cancer was found in the contralateral prostate in only 1 of 27 men. No adverse events above Clavien-Dindo grade 2 were encountered.

Conclusions: Hemigland cryoablation, when rigorously evaluated by all utilities of magnetic resonance imaging guided biopsy, appears to eliminate clinically significant cancer in 82% of men, a success rate that endures for at least 18 months.

Keywords: biopsy; cryosurgery; prostatic neoplasm.