02 Feb 2012
The mere mention of the word “surgery” often brings fear and trepidation to many patients.
The fear of pain, blood loss and other complications are contributing factors.
The option of having surgery without a scalpel is very attractive to many patients, but is it possible?
Mr X is a 69-year-old retired engineer who had been diagnosed with early prostate cancer.
He was presented with the available options for treating his condition.
As his disease was detected early, one of the options was watchful waiting.
This meant that he faced the psychological burden of having cancer and not having any treatment.
There was a small chance that his disease might progress during this period of monitoring.
Alternatively, he could choose more proactive conventional treatment that might include surgery or radiation therapy.
However, these are associated with risks such as urinary incontinence (not being able to control urination) and sexual impotence (not being able to have an erection).
He was also offered a third option – a new method that is now being tested, called magnetic resonance guided focused ultrasound surgery.
It has been made available to patients of the Singapore General Hospital (SGH) Urology Centre and National Cancer Centre Singapore (NCCS) as part of a phase 1 clinical trial to test for safety and clinical effectiveness.
The trial, a collaboration between the department of oncologic imaging at NCCS and the department of urology at SGH, started in July 2010. We hope to enrol 40 patients in Singapore.
Ultrasound is considered a very safe mode of medical imaging. There is no harmful effect when an individual beam of ultrasound passes through tissue.
However, if we concentrate up to 1,042 intersecting beams of focused ultrasound energy with extreme precision onto a target as small as a grain of rice that is deep within the body, we can achieve a focal heating effect.
This is analogous to the way in which a magnifying glass can focus the sun’s rays to burn a hole in a leaf.
With this new system, doctors are able to use magnetic resonance imaging (MRI) to accurately guide focused ultrasound waves to generate heat and maintain high temperatures within the target area of tissue for a sufficient length of time, resulting in cell death.
This process is known as sonication and is repeated until the entire cancerous region is treated.
Instead of physically inserting a temperature probe into the body to monitor the temperature, MRI is also used to monitor the actual temperature rise within the target organ to ensure adequate treatment.
This other function of MRI is also important for the doctors to ensure there is no collateral damage to other structures or organs adjacent to the treated area.
It is the collateral damage to surrounding tissue during surgery or radiation therapy that often results in complications such as sexual impotence.
The beauty of this treatment is that it is entirely non-invasive.
After the entire treatment is completed, an MRI scan is performed with an injection of a dye to ensure the treated area has been destroyed and is without blood supply.
Mr X made a bold decision to be enrolled in the trial.
He was under both regional anaesthesia and sedation throughout the procedure.
A probe containing the ultrasound transducer was inserted into the rectum and used to deliver the focused ultrasound beams for treatment.
A few hours later, the treatment was completed and Mr X was monitored in the ward overnight.
He did not have a surgical wound and there was no blood loss, unlike in conventional surgery.
He was discharged the next day and did not need a lengthy period of post-surgical recovery and rehabilitation and was able to return to his usual weekend routine two days later.
As this treatment is still being evaluated as part of a clinical trial, we are closely monitoring all patients who have been treated to ensure safety and effectiveness.
This means all treated patients are closely followed up for two years to ensure that the cancer does not return in the treated areas.
We are looking forward to the day when surgery for early prostate cancer can be done safely without a scalpel.
Dr Kwek Jin Wei is a senior consultant radiologist who leads the magnetic resonance imaging section at the department of oncologic imaging at the National Cancer Centre Singapore.
He is collaborating on the magnetic resonance guided focused ultrasound surgery trial with Professor Christopher Cheng, who is the principal investigator of the trial and senior consultant at the department of urology at Singapore General Hospital.
Email: corporate@nccs.com.sg
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