The pattern of prostate cancer local recurrence after radiation and salvage cryoablation

Abstract

Objective: We assessed the pattern of local recurrence after salvage cryoablation of the prostate, and the impact of local recurrence on intermediate-term outcome. Methods: One hundred twenty-two patients who underwent salvage cryoablation were studied after a mean follow-up of 56 months. Serial prostate biopsy was carried out after cryoablation. The histopathology of prostate biopsies before and after cryoablation were compared. The prognostic value of post-cryoablation biopsy was assessed with the Cox regression method. Results: 23.1% of patients had a positive biopsy for prostate cancer following salvage cryoablation. Most cancer recurrences occurred in the apex (51.5%), base (21.2%) and seminal vesicles (18.2%). The presence of cancer at the base of the prostate was found to be a prognostic factor for eventual biochemical failure. Overall 5-year biochemical disease-free survival (bDFS) was 28%, however patients with cancer at the base of the prostate had a 5-year bDFS of 0%. Conclusion: Cancer recurrences occurred in areas where aggressive freezing was avoided as it might result in serious problems (e.g., urethro-rectal fistula and incontinence). Post-cryoablation biopsies and the location of persistent disease are of prognostic value.

Anatomical and dosimetric assessment of the prostate apex: A pilot comparison of image‐guided transperineal ultrasound to conventional computed tomography simulation

“…[3][4][5][6] accurate delineation of this anatomical region is of vital importance in radiotherapy contouring and treatment delivery. 13,14 In this stead, it is important to advocate the use of all available adjunct imaging modalities when delineating the prostate apex.…”

“…The interobserver variability in prostate contouring is well published, and given the apex is a critical site of extraprostatic extension and recurrence after therapy 3–6 . accurate delineation of this anatomical region is of vital importance in radiotherapy contouring and treatment delivery 13,14 . In this stead, it is important to advocate the use of all available adjunct imaging modalities when delineating the prostate apex.…”

Review of the efficacy and safety of cryoablation for the treatment of small renal masses

“…27 In a prostate cancer model, where CA has been more extensively studied, positive biopsies post-CA have been found in up to 23.1% of patients in a postradiotherapy CA model. 28 While it may be stipulated that the prostate cancer model is not necessarily an apt comparison given the multi-focal nature of prostate cancer versus a solid CSS: cancer-specific survival; RCC: renal cell carcinoma; CR: complete response; CA: cryoablation; RFA: radiofrequency ablation; RFS: recurrence-free survival; CT: computed tomography; MRI: magnetic resonance imaging. *Percentages were calculated on a patient number basis; a Extension of the ice ball beyond the tumour margin and post-ablation images showing no contrast enhancement in the tumour parenchyma; b Not defined; c Completion of the cycle of a 10-minute freeze, 8-minute active thaw, and 10-minute repeat freeze with the ice ball covering the entire lesion and extending at least 5 mm beyond its border; d Complete lack of enhancement of a previously enhancing mass; e Complete ablation of macroscopic tumour as shown at imaging follow-up; f No evidence of central or nodular enhancement after treatment; g Extension of the ice ball beyond the tumour margin and postablation imaging findings of no contrast enhancement in the area encompassing the original tumour; h Absence of death from renal cancer; i No evidence of radiographic recurrence at the site of CA, regardless of the lesion pathology; j Not defined; k Continued contrast enhancement on postoperative CT; l An involuted scar or fibrosis without evidence of growth or enhancement on the most recently available imaging study; m Growth of a persistent renal mass, as well as the persistence or development of heterogeneous peripheral enhancement within any persistent mass.…”

Cryotherapy in prostate cancer

“…Interestingly, they found the post-treatment presence of cancer at the base of the prostate to be a prognostic factor for biochemical failure, with a 0% five-year bDFS in their series of 122 salvage cryoablation patients. 47 A recent retrospective analysis was performed by Pisters et al who compared salvage cryotherapy to salvage prostatectomy. 48 His group analysed patients with PSA less than 10 ng/ml, post-radiation therapy biopsy showing Gleason score 8 or less and prior radiation therapy alone without pre-salvage or post-salvage hormonal therapy.…”