HIFU stands for High Intensity Focussed Ultrasound. It is most commonly performed with ultrasound guidance which allows the focussed ultrasound to be delivered accurately to the area containing the tumour.
It works by heating up the area being targeted to a sufficiently high temperature that the cancer cells die.
It can be used for small lesions as a primary treatment modality, but it is one of the effective treatments available for a post-radiotherapy recurrence that consists of a small lesion within the Prostate Gland.
It is usual to go home on the same day of the treatment.
It’s a treatment modality to consider when looking at the Focal Ablations that are on offer at your Cancer Centre.
Focal Laser Ablation
Using MRI-guidance a Laser probe is positioned at a lesion within the Prostate Gland.
The principle of focal laser ablation therapy is to destroy a tissue target using laser radiation energy. The resulting rapid temperature elevation of the targeted tissue results in in vivo tissue destruction. Prostate tissue is well suited for focal laser ablation due to its optical absorption rate without excess vascularity, which allows for finely controlled ablation.
Effective focal laser ablation for the treatment of prostate cancer requires 1) accurate delivery of the laser energy to the target tissue, 2) sufficient thermal destruction to reliably destroy the target tissue, and 3) minimal thermal destruction to surrounding tissues. Each step provides its own set of technical challenges, but ongoing advances in image acquisition and analysis, bioheat transfer modelling, and laser delivery technology make laser ablation of prostate cancer very feasible.
As with HIFU you should be able to go home on the same day as the procedure is performed.
Electroporation – “NanoKnife”
The technical name for this process is Irreversible Electroporation or (IRE). It is a particularly interesting procedure that kills all types of cancer cells and so is widely applicable. It does not rely on heat, or cold, to eradicate the cancer. The cancerous cells are killed by an electric field.
The most basic setup for the NanoKnife is two electrodes which are positioned in the prostate gland using ultrasound guidance. A voltage, typically 3,000 volts, is applied between these electrodes for a fraction of a second and the cells within the resulting field are eradicated. In practice, to keep the body at zero volts one electrode will be set to +1,500 volts and the other to -1,500 volts. A larger lesion can be handled by inserting more than two electrodes in the prostate gland and then arranging to energise them in pairs.
Once the treatment is complete the electrodes are withdrawn leaving very limited damage to the area. And unlike other treatments this can be performed many times as appropriate to need.
The particular setup and process is simulated in software before the actual treatment is performed. A typical treatment can take as little as 20 minutes, including setup. The patient can go home on the same day and will return a few days later so that the result of the treatment can be established with an MRI scan.
Following this, MRI scans are taken at regular intervals – typically every few months. It is found that the scarred area in the prostate gland shrinks with time.
This treatment modality, as well as being ideal for a small recurrence in the prostate gland, can be used very effectively as a primary treatment in carefully selected patients thereby removing the requirement for radical treatments such as surgery and radiotherapy.
This is definitely a treatment procedure to “keep an eye on”.
Brachytherapy can be used as a Focal Ablation technique.