Five-year retrospective, multi-institutional pooled analysis of cancer-related outcomes after cryosurgical ablation of the prostate.

OBJECTIVES: To define the potential role of cryosurgical ablation of the prostate (CSAP) as a treatment option for patients with localized prostate carcinoma (PCA), we performed a retrospective outcomes analysis of a large database of patients undergoing CSAP constructed from five institutions and compared this with matching outcomes from contemporary reports of patient outcomes after radiotherapy. METHODS: A total of 975 patients who underwent CSAP as primary therapy from January 1993 to January 1998 with sufficient outcomes data available were identified. Patients were stratified into three groups on the basis of their clinical features. Biochemical-free survival (BFS), post-CSAP biopsy results, and post-CSAP morbidities were calculated and recorded. RESULTS: The median follow-up for all patients was 24 months. The percentages of patients in the low, medium, and high-risk groups were 25%, 34%, and 41%, respectively. For prostate-specific antigen thresholds of less than 0.5 and less than 1.0 ng/mL, the 5-year actuarial BFS ranged from 36% to 61% and 45% to 76%, respectively, depending on the risk category. Overall, the positive biopsy rate was 18%. Morbidities included impotence in 93%, incontinence in 7.5%, rectourethral fistula in 0.5%, and transurethral resection of the prostate in 13% of patients (10% approved warming catheters versus 40% nonapproved). CONCLUSIONS: For each risk group, the 5-year BFS and positive biopsy rate after CSAP was comparable to matching outcomes reported after radiotherapy. Morbidities also seemed comparable, with impotence rates higher and rectal injury rates lower after CSAP than after radiotherapy. These data indicate that CSAP can be performed with low morbidity and can produce cancer-related results comparable to those reported for patients undergoing radiotherapy.

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

OBJECTIVES: To describe and assess the efficacy for increased glandular destruction 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 uses 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 using 5 cryoprobes. All cases were consecutive. To ensure that the groups were 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 = 0.023). Complete glandular ablation for the 5-probe and 6 to 8-probe methods was 39% and 53%, respectively, and the difference was not significant (P = 0.072). However, when one combined the complete glandular ablation group with the none to few residual acini group, 67.5% for the 5-probe method and 88.9% for the 6 to 8-probe method, a significant difference was 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 were 0.19 and 0.1 versus 0.11 and 0.07 ng/mL, respectively, a significant difference (P = 0.02). No difference was found in rates of tumor persistence or complications. CONCLUSIONS: A revised method for cryosurgery using 6 to 8 cryoprobes has proved 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 even shortened learning time. These innovations have permitted a closer approach to the goal of complete glandular destruction.

Perivascular and intralesional tissue necrosis after hepatic cryoablation: results in a porcine model.

BACKGROUND: Cryosurgical ablation of malignant hepatic tumors is being increasingly used for definitive treatment of metastatic colorectal and primary hepatic tumors. The lack of tumor necrosis near vessels that results from inadequate freezing may contribute to local recurrence and thus limit the applications of this therapy. This study was designed to determine whether single-freeze cryoablation could cause necrosis of both the pervascular and intralesional hepatic parenchyma. METHODS: Ten pigs were treated with one 15-minute cycle of cryoablation. Five additional animals were treated with overlapping cryolesions to simulate a double freeze. After 24 hours, animals underwent reoperation with portal vein cannulation and infusion of formalin. Serial sectioning and hematoxylin and eosin staining of cryolesions were performed. RESULTS: Complete cell death was visualized within all cryolesions. There was no difference between once or twice-frozen tissue. Vessels within or adjacent to cryolesions showed necrosis of hepatic tissue up to the vessel wall. No sections revealed incomplete necrosis of perivascular hepatic parenchyma. CONCLUSIONS: Single-freeze cryoablation results in necrosis of intralesional hepatic parenchyma without added benefit from repeat freezing. Complete necrosis of the perivascular tissue suggests that cryosurgical ablation can effectively cause necrosis immediately adjacent to vessels without concerns of incomplete ablation resulting from the heat sink effect.

Cryosurgery as a treatment for prostate carcinoma: results and complications.

BACKGROUND: There has been a resurgence of interest in cryosurgical ablation of the prostate for the treatment of carcinoma. This is due to recent advances in cryosurgical technology, which have resulted in relatively lower morbidity. The objective of this study was to evaluate the effectiveness of ultrasound-guided cryosurgical ablation of prostate carcinoma. METHODS: Eighty-three patients who had biopsy-proven prostate carcinoma underwent cryosurgical ablation of their entire prostate gland. The initial group of 12 patients had their procedures performed under ultrasound guidance only. The other 71 patients had cryosurgery performed with temperature monitoring in combination with ultrasound guidance. Twelve patients who had positive biopsies underwent a second cryosurgical procedure. All patients had prostate specific antigen (PSA) levels measured at 3, 6, 12, 18, 24, and 30 months after cryosurgery. Ultrasound-guided sextant biopsies were performed at 3-6, 12-18, and 24 months. RESULTS: The median PSA dropped by 95%, from a preoperative value of 4.3 ng/mL to 0.2 ng/mL 30 months after cryosurgery. The authors experienced a high failure rate (positive biopsies) of 83% for the initial group of 12 patients who did not have temperature monitoring during the cryosurgical procedure. This was in contrast to a success rate of 90% (negative biopsies) for the next 71 patients, who did have temperature monitoring (P < 0.05, chi-square test). Twelve patients underwent a second cryosurgery, and the success rate for this group was 91% (11 of 12 patients). The combined success rate for both the first cryosurgery and the second was 94% (62 of 77 patients). Complications included urethral sloughing, urinary incontinence, impotence, bladder neck contracture, and bladder contracture. The majority of patients recovered rapidly from their cryosurgical procedures and were able to resume normal activities 3-4 weeks afterward. CONCLUSIONS: These preliminary results demonstrate that cryosurgical ablation of the prostate is a viable treatment option for prostate carcinoma. In the authors' experience, ultrasound alone may not be adequate for monitoring the entire cryosurgical procedure. The authors found that temperature monitoring shortened their learning curve, enabled them to freeze prostate tissue more aggressively, and may have contributed to their overall success.