CRYOSURGICAL TREATMENT OF LOCALIZED PROSTATE CANCER (STAGES T1 TO T4) 121

protect the bladder neck and external sphincter. For unknown reasons we have had less difficulties with urethral slough than Shinohara et a1 and others. We found that leaving a Foley catheter in the urethra for 3 weeks after cryosurgery helps decrease our slough rate to less than 10% and only 5% of the patients require transurethral resection.

Less than 10% of the patients in this series were treated with radiation therapy before cryosurgery. Although the numbers are small, an increased incidence of urethrorectal fistulas was de- tected in these patients. We also found an increased number of complications in patients after radiation therapy, particularly in regard t o fistulas and incontinence. The major complication of fistula to the rectum is 8% in our hands and nearly always necessitates cystoprostatectomy. Because of the increased rate of iatrogenic injuries in these patients, we believe that only the most experienced operators should even attempt cryosurgery in this SOUP.

The authors are to be commended for this interesting and provoc- ative study. Their understanding of the importance of meticulous attention to technical factors is reflected in the high success rate for tumor ablation with a low associated morbidity rate. Such studies will be important as bench marks in the future study of cryosurgery. Of course, long-term results are necessary before the ultimate role of

cryosurgery for the treatment of prostate cancer can be definitively known.

Fred Lee Department of Radiology Crittenton Hospital Rochester, Michigan

REPLY BY AUTHORS

Although 36% of our patients with stage Tlc prostate cancer had a detectable PSA after cryotherapy, only 1 had an increasing PSA at 2 years of followup and the remainder had low PSA levels. The significance of a marginally detectable PSA after cryotherapy with respect to residual disease is not known but it has been shown that a low PSA (less than 1 ng./ml.) a h r radiation therapy can be asso- ciated with prolonged clinical remission.' This finding may also be true for cryotherapy. This report and others cited suggest that cryo- therapy results in epithelial destruction. Careful long-term followup of patients receiving no adjuvant therapy after cryoblation is neces- sary before the durability of this procedure is known.

1. Geist, R.W.: Reference range for prostate-specific antigen levels after external beam radiation therapy for adenocarcinoma of the prostate. Urology, 45: 1016, 1995.