THE EFFICACY OF CRYOSURGICAL ABLATION OF PROSTATE CANCER: THE UNIVERSITY OF CALIFORNIA, SAN FRANCISCO EXPERIENCE

Abstract

Purpose We analyze biopsy and prostate specific antigen (PSA) results following cryosurgery for patients with clinically localized prostate cancer. Materials and Methods A total of 176 patients underwent 207 cryosurgical procedures for clinically localized (stages T1 to T4) prostate cancer using a multiprobe cryosurgical device. Cancer stage was T1 in 8.7%, T2 in 30%, T3 in 59% and T4 in 2.3% of the 176 patients. Neoadjuvant androgen deprivation was delivered to 101 patients (57%). End points used to determine efficacy of the procedure included analysis of posttreatment serum PSA characteristics (nadir and nonrising status) and biopsy results (absence of cancer). Cryosurgery was considered successful if PSA reached a nadir of less than 0.5 ng./ml. and did not increase by more than 0.2 ng./ml. on 2 consecutive occasions. Mean followup for the entire group was 30.8 months, with 122 patients (60%) followed for 24 or more months and 75 (36%) followed for 36 or more months. Results Serial PSA data was available after 181 initial and repeat procedures. Nadir PSA was undetectable in 88 patients (49%), between 0.1 and 0.4 ng./ml. in 39 (21%) and 0.5 ng./ml. or greater in 54 (30%) following cryosurgery. After 78 of these procedures (43%) serum PSA reached a nadir of less than 0.5 ng./ml. and failed to increase greater than 0.2 ng./ml. on at least 2 occasions. Prostate biopsy was performed following 167 procedures and was positive after 64 (38%). Conclusions Cryosurgery was associated with favorable serum PSA characteristics in 49% of patients 3 years after treatment. Undetectable PSA nadir and pretreatment PSA 10 ng./ml. or less were associated with a favorable outcome, with a biochemical disease-free survival of 77% and 61% 3 years after treatment, respectively.