Cryosurgery for prostate cancer: Improved glandular ablation by use of 6 to 8 cryoprobes

Objectives. To describe and assess the efficacy for increased glandular des truction by using 6 to 8 cryoprobes in place of the traditional 5 probes. Methods. In April 1996, a revised method for cryosurgery was begun that use s 6 to 8 cryoprobes, and by July 1997, 81 men had been treated. This group was compared retrospectively to our last 82 cases done before April 1996 us ing 5 cryoprobes. All cases were consecutive. To ensure that the groups wer e similar, comparison was performed of entrance prostate-specific antigen ( PSA), clinical stage, and Gleason score. Six months after cryosurgery, PSA and residual epithelial acini were compared between the two groups. Results. The two groups were comparable for all the above parameters (P > 0 .05). The degree of overall glandular kill was greater for the 6 to 8-probe method (P = 0.025). Complete glandular ablation for the 5-probe and 6 to 8 -probe methods was 39% and 53%, respectively, and the difference was not si gnificant (P = 0.072). However, when one combined the complete glandular ab lation group with the none to few residual acini group, 67.5% for the 5-pro be method and 88.9% for the 6 to 8-probe method, a significant difference w as found (P = 0.001). The odds of having many remaining acini versus having none to few were 3.5 times greater in the 5-probe group than in the 6 to 8 -probe group. The mean and median PSA for the 5- and 6 to 8-probe groups we re 0.19 and 0.1 versus 0.11 and 0.07 ng/mL, respectively, a significant dif ference (P = 0.02). No difference was found in rates of tumor persistence o r complications. Conclusions. A revised method for cryosurgery using 6 to 8 cryoprobes has p roved to be more effective for near-glandular ablation than the traditional 5-probe method. It was easily applied, had a wide margin of safety, and ev en shortened learning time. These innovations have permitted a closer appro ach to the goal of complete glandular destruction. UROLOGY 54: 135-140, 199 9. (C) 1999, Elsevier Science Inc.