The biochemical efficacy of primary cryoablation combined with prolonged total androgen suppression compared with radiotherapy on high-risk prostate cancer: a 3-year pilot study

Abstract

To gain beneficial effects in the management of high-risk prostate cancer, an integrated approach that combines local therapy and androgen deprivation therapy (ADT) was used. We compared biochemical responses between primary cryosurgical ablation of the prostate (CSAP) combined with prolonged ADT and radiation combined with ADT, which is the established modality in high-risk disease. A total of 33 high-risk patients received CSAP combined with ADT for 3 months before and up to 24 months after treatment. This patient group was matched with another 33 patients who had undergone three-dimensional conformal radiation therapy (3D-CRT) with the same protocol for ADT. Biochemical recurrence (BCR) was assessed by the American Society for Therapeutic Radiation Oncology (ASTRO) definition, the Phoenix definition and a prostate-specific antigen (PSA) cutoff of 0.5 ng mL(-1). Median follow-up was 61.0 ± 11.9 months for the CSAP + ADT group and 86.0 ± 15.8 months for the 3D-CRT + ADT group. In the CSAP group, major complications including rectourethral fistula and incontinence were not noted. In the CSAP + ADT group, 57.0% had BCR using the ASTRO definition, 21.2% using the Phoenix definition and 54.5% using a PSA cutoff of 0.5 ng mL(-1). In the 3D-CRT + ADT group, 54.5%, 21.2% and 54.5% had BCR using the ASTRO, Phoenix and PSA definition, respectively. In the CSAP + ADT group, the BCR-free survival (BRFS) was 54 ± 10 months using the ASTRO definition, 65 ± 5 months using the Phoenix definition and 51 ± 4 months using a PSA cutoff of 0.5 ng mL(-1). In the 3D-CRT + ADT group, the BRFS was 68 ± 12, 93 ± 19 and 70 ± 18 months using the ASTRO, Phoenix and PSA definition, respectively. By the log-rank test, the BRFS values for each group were not statistically different. This intermediate-term result indicated that primary CSAP combined with prolonged ADT offers a parallel biochemical response compared with radiotherapy in high-risk prostate cancer.

Figure 1

Biochemical recurrence-free survival of cryoablation with hormone therapy versus radiotherapy with hormone therapy, using the American Society for Therapeutic Radiation Oncology (ASTRO) definition (A), Phoenix definition (B) and prostate-specific antigen (PSA) cutoff of 0.5 ng mL⁻¹(C).