Hot needle that spares men from impotence by destroying cancer cells
02:10 GMT, 3 July 2012
Doctors are using a hot needle to ‘cook’ prostate cancer.
The device, which is placed against the diseased prostate gland, uses high temperatures to destroy cancer cells, but leaves the healthy surrounding tissue untouched.
Surgeons say that the fine needle, which is no more than 2mm across, allows them to destroy only the part of the prostate that is diseased, and reduces the risk of side-effects such as impotence and incontinence.
Prostate is the most common male cancer, accounting for one in four of all tumours diagnosed in men
They are now trialling the technique, which has been used previously to treat breast and kidney tumours, on 60 men with early-stage prostate cancer.
This is the most common male cancer, accounting for one in four of all tumours diagnosed in men.
In the UK, there are more than 40,000 cases a year and 10,000 deaths.
There are a number of different treatments, depending upon whether the cancer is contained within the gland, or has spread just outside the prostate or to other parts of the body.
For localised cancers, treatments include watchful waiting (also known as ‘active surveillance’), where doctors closely monitor the development of a tumour, or removal of the gland in a procedure called a radical prostatectomy.
While treatments can be highly effective, there is a risk of side-effects due to nerves being damaged during the procedure.
Because of this, there is increasing interest in so-called focused therapies that use high-energy waves to destroy the cancer.
One technique that is increasingly used is high-intensity focused ultrasound (HIFU), which uses soundwaves to destroy the cancer.
Another technique is radio-frequency ablation, which uses a type of electric current that generates heat at the end of a needle-like electrode.
This is placed into the tumour and destroys the tissue around the tip of the device.
One technique that is increasingly used is high-intensity focused ultrasound (HIFU), which uses soundwaves to destroy the cancer
Scientists believe that this technique can be used to treat more people than high-intensity focused ultrasound.
Professor Raj Persad, urological surgeon at the Bristol Royal Infirmary and Bristol Urological Institute, explains this is because the energy used in high-intensity focused ultrasound is weaker than that used in radio-frequency ablation.
This means ultrasound cannot treat large prostates (because the beam will not penetrate deep enough); it also can’t be used on men who have prostate stones — hard calcium deposits common in older men.
This is because the beam will be blocked — ‘even worse it can be reflected back towards the rectum, causing potential harm to the tissue,’ says Professor Persad.
Radio-frequency ablation does not have these complications, and is now being used in a trial at the Lee Moffitt Cancer Centre and Research Institute in the U.S.
Doctors will perform the procedure on 60 men with early-stage prostate cancer that has not spread outside the gland.
Under general anaesthetic the needle will be inserted through the perineum (the area between the scrotum and the bottom) and doctors will use imaging such as CT scans or MRI to guide the needle into place.
During the hour-long operation the device delivers a blast of electricity at a power of around 20 watts (an electric shaver uses around 50 watts of power).
After six months, the doctors will evaluate the patients’ side-effects, including incontinence, bowel function and impotence.
Commenting on the research, Professor Persad says: ‘This is an interesting trial, and is part of the sea-change in the philosophy of prostate cancer treatment.
‘It represents an attempt to treat only the portion of the gland involved with cancer and avoid unnecessary damage to surrounding structures, which is a risk with “whole gland treatment” such as radical prostatectomy or radical radiotherapy.’
But he cautions neither approach can be used for advanced disease. ‘Not all tumours can be treated in this way — extremely aggressive or high-risk prostate tumours are not suitable for this technique.’
Regularly eating fried or barbecued white fish may increase the risk of advanced prostate cancer, according to a U.S. study.
Researchers at the University of Southern California looked at the diets of around 3,000 men, including 717 with localised prostate cancer and 1,140 with advanced cancer.
A high intake of white fish (two or more servings a week) cooked at high temperatures — pan-fried, oven-broiled or grilled — was linked to double the risk of advanced prostate cancer.
No link was found among men who cooked fish at low temperatures (baking or poaching).
Dark fish such as sardines cooked at low temperature reduced the risk of the disease.
It’s thought high temperatures may lead to the formation of cancer-causing chemicals in the fish — previous laboratory studies have found charred food can produce chemicals (mutagens) that alter DNA and turn a cell cancerous.
‘Our results suggest that avoiding high-temperature cooking methods for white fish may lower prostate cancer risk,’ the researchers said.