Emerging minimally invasive procedures for focal treatment of organ-confined prostate cancer

Abstract

Prostate cancer is the most common malignancy amongst American men. However, the majority of prostate cancer diagnoses are of low risk, organ-confined disease. Many men elect to undergo definitive treatment, but may benefit from focal therapy to maintain continence and potency. This review reports the mechanism of action and outcomes of emerging focal therapies for prostate cancer. We report the mechanism of action of focal cryotherapy, high intensity focused ultrasound, focal laser ablation, and irreversible electroporation. In addition, we reviewed the largest studies available reporting rates of urinary incontinence, erectile dysfunction, biochemical recurrence-free survival (ASTRO), and post-operative adverse events for each procedure. Each treatment modality stated has a unique mechanism in the ablation of cancerous cells. Genito-urinary symptoms following these studies report incontinence and erectile dysfunction rates ranging from 0-15% and 0-53%, respectively. Biochemical disease-free survival was reported using the ASTRO definition. Some treatment modalities lack the necessary follow-up to determine effectiveness in cancer control. No focal therapy studies reported serious adverse events. These minimally invasive procedures are feasible in a clinical setting and show promising functional and disease control results with short to medium-term follow-up. However, each treatment requires additional robust prospective studies as well as its own unique domain to determine biochemical recurrence free survival to properly determine their role in treatment of organ-confined prostate cancer.

Patient-reported quality of life progression in men with prostate cancer following primary cryotherapy, cyberknife, or active holistic surveillance

“…Given the resolution of the bowel symptoms, our patient cohort does not appear to be subject to chronic radiation damage such as stricture, diminished rectal compliance, or decreased storage capacity 32 . Also, the difference in severity of bowel function between CK and Cryotherapy relative to AHS may be due the differences in underlying mechanism of action of these treatment modalities 16 , 34 .…”

“…Cryotherapy is the controlled freezing of the prostate gland, wherein freeze-thaw cycles trigger protein denaturation, loss of blood supply, and apoptosis of prostate cells 16 . Cryotherapy is associated with an excellent biochemical recurrence-free survival rate – approximately 75% 2 years after treatment 17 .…”

Moderately hypofractionated prostate external-beam radiotherapy: an emerging standard

“…Concurrently, there are several other ablative approaches available including cryotherapy, high intensity focussed ultrasound and electroporation, most of which involve a single treatment administered without the need for an overnight stay in hospital. 14 Although the evidence supporting most of these ablative strategies is non-randomized, and some of these tensions tend to be opposing, both from a patient access aspect as well as resourcing and retaining appeal amongst numerous competing treatment strategies, there is merit in exploring hypofractionated approaches beyond the biological and technological rationales already outlined.…”

Salvage focal cryosurgery may delay use of androgen deprivation therapy in cryotherapy and radiation recurrent prostate cancer patients

“…Advancement in new technology and better patient selection is paving the path to cryotherapy, a minimally invasive treatment option for patients with organ confined PCa [8,9]. Cryotherapy has been well studied in both primary and salvage settings and can involve partial (hemiablation or focal lesion ablation) or total ablation of the prostate [10,11]. Focal and total salvage cryotherapy has comparable oncologic outcomes but focal ablation has been shown to minimise the morbidities associated with radical surgery [4,12].…”