Treatments for prostate cancers localised to the prostate have long been aimed at treating the whole prostate either by surgical removal or by radiotherapy. In many other cancers, such as kidneys, a treatment of part of the organ has been used as a first line treatment. In prostate cancer, these treatments, often called focal therapies, have been slow to develop and emerge as an option for men.
A range of focal therapies are available across Australia at a limited range of sites through the private and public systems. Among these are focal brachytherapy, laser ablations, such as Profocal, High Intensity Focused Ultrasound (HIFU) and Irreversible Electroporation (IRE) or Nanoknife.
In a procedure similar technique to a transperineal biopsy, IRE uses a series of high voltage electrical pulses between needle electrodes positioned in the prostate, to create small holes in the membrane of prostate cells . This process causes normal chemicals which sit outside the cell to enter the cell leading to cell death. It appears that IRE may have less impact of the surrounding tissue leaving blood vessels, the urethra and bladder neck less affected than with other techniques.
IRE may be an option for those with prostate cancer if the cancer is:
- Intermediate risk Gleason 7 or lower
- A single tumour identifiable on MRI and/or PSMA PET scan
- Generally, a PSA less than 15
- Confirmed on biopsy to have a Gleason Score of 7 (less than 1cm in core biopsy) or large volume (greater than 1cm in core biopsy) Gleason 6 cancer.
- confirmed on biopsy that there is no other significant cancer outside the MRI lesion.
Patients must be:
- fit for a general anaesthetic with a life expectancy of at least 10 years.
- deemed suitable for focal therapy by a multidisciplinary meeting.
- Willing to undergo further monitoring of the cancer with follow up PSA testing, MRI and further prostate biopsy.
IRE may also be used in cases where cancer has recurred within a single lesion in the prostate after initial treatment with external beam radiotherapy or brachytherapy. Previously treatment options in this case have included salvage prostatectomy or in many cases androgen deprivation therapy.
Following the procedure, patients usually are discharged on the same day or may stay overnight. Patients usually go home with a catheter to drain the bladder for 2-5 days.
Short term side effects usually include:
- Pain or discomfort in the prostate region which usually subsides.
- Blood in the urine for approximately 6 weeks
- Pain when passing urine.
- Urinating more frequently
- Possible urinary retention
- Urinary tract infection
- In some cases, temporary urinary incontinence
Longer term urinary and sexual side effects usually occur less often compared to radical prostatectomy or radiotherapy but may include:
- A loss of ejaculate or retrograde ejaculation
- A reduced ability to get or maintain erections.
A recent multicentre study reported that urinary function actually improved compared to baseline function 6-months post IRE. A recent systematic review reported between 96% and 100% of patients did not require a continence pad. Similarly, those with pre op erections firm enough for intercourse more than half the time, reported maintaining this level of erectile function in more than 70% of cases up to 2 years follow up.
Patients must commit to ongoing follow up following IRE. This will include MRI, PSA testing and biopsy, and may include PSMA PET imaging in some instances. In an international multicenter study up to 24% of repeat biopsies confirmed clinically significant cancer was still present. In Australian studies, 17% of men treated with IRE required salvage radical treatment up to 5 years post IRE. This recurrence can be retreated with further IRE, or a move to radical prostatectomy or radiotherapy.
Currently, IRE is only available in 1-2 public hospitals nationally, and a number of private hospitals in NSW, VIC, QLD and WA. Currently, there is a proposal under consideration by the Medicare Services Advisory Committee (MSAC) to have IRE subsidised by Medicare. Due to this, patients typically need to self-fund all focal therapies and are currently facing significant out of pocket costs for IRE. IRE is not yet covered by Medicare or most private health funds because it is considered an experimental or emerging therapy for prostate cancer and other tumours.
