Cryoprostatectomy: Histological Changes Elucidated by Serial Biopsies

Abstract

Following transurethral freezing of the prostate at-160°c for an average of 13 minutes in 87 patients, the histomorphological changes were examined in serial biopsies at varying intervals after the operation. Oedema and extravasation were demonstrated immediately after thawing the gland. During the first few postoperative days, further signs of degenerative vascular damage were found, with interstitial bleeding, while actual necrosis dominated from 10 days to 10 weeks after freezing. After this period, the biopsies showed increasing reparative changes and proliferating prostate tissue with varying degrees of fibrosis. The histological changes are compared with the clinical course. It is concluded that freezing is immediately followed by recognizable morphological changes. Where indicated, the surgical extraction of any retained necrotic tissue should take place at a late stage, where the reparative processes with demarcation of the necrotic tissue have developed. The intervention does not result in neoplastic prostate morphology, and in view of the subcapsular proliferation prostate tissue which remains, the procedure should be regarded as a resection of the prostate.