HISTOPATHOLOGY OF THE FROZEN PROSTATE THE MICROSCOPIC BASES OF PROSTATIC-CARCINOMA CRYOABLATION

In the last few years percutaneous cryoablation surgery of the prostat e has been reintroduced as an alternative means to treat prostatic car cinoma. Advantages of the technique include local effectiveness in era dicating tumors, minimal morbidity rate and lower costs when compared to radical surgery. We report a study documenting the histopathologica l changes seen in 317 biopsy specimens obtained from 30 patients (age range 59 - 83 years, median 73 years) treated with cryosurgical ablati on for prostate cancer. Pre- and postoperatory assessment was inclusiv e of plain clinical, laboratory and instrumental data (digital rectal examination, transrectal ultrasound scan, serum prostatic specific ant igen concentration) and systematic biopsies obtained from conventional and modified prostate sextants. Fifteen patients had tumors extending through the prostate capsule (pT3 and pT4). Six patients had stage pT 1 tumors and 9 had stage pT2. Tissues were sampled at 3, 6 and between 12-18 months postoperatively. The histologic findings, in decreasing order of frequency, were: full cove fibrosis, necrosis, granulation ti ssue, basal cell hyperplasia, cell swelling, hemosiderin deposits, chr onic inflammation, thick nerves and prostatic hyperplasia. Necrosis wa s of the coagulative type, sometimes associated with nuclear debris, a nd seen as relatively short interval from cryotherapy. Fibrosis with h yaline qualities was seen especially at 12-18 month interval. The pres ence of necrosis, as well as granulation tissue, hemosiderin deposits and cell swelling, strongly correlate to intervals from cryosurgical a blation. Residual tumor tissue was focal (0.5-1 mm) and recognizable i n 9 cores from 4 patients (13.3%) sampled especially from the prostati c apex. Incipient tumor necrosis was seen in 11 cores, without particu lar distribution. These findings indicate that cryosurgery results in distinctive changes in both tumoral and non-tumoral prostate tissue. K nowledge of the histopathologic Patterns is important since it provide s the clinicians with information on treatment efficacy or failure, an d could assist in the selection of larger groups of patients eligible to cryosurgical ablation.