Cancer patients receiving radiotherapy may be at higher risk of vascular diseases and stroke: study
Researchers warn cancer treatment could lead to permanent disability a decade after therapy
Patients who receive radiotherapy to treat cancer in their head or neck may be more likely to develop severe vascular diseases including blocked blood vessels, leading to a higher risk of a stroke, a recent study has found.
Carotid stenosis - the narrowing of the inner surface of the carotid artery - induced by radiation could occur a decade after the therapy and could lead to permanent disability, researchers warned.
But the study also found that at least one method of treating radiation-induced stenosis is highly effective - carotid angioplasty and stenting (CAS), in which a mesh tube is inserted within diseased blood vessels to prevent the narrowing of the carotid artery.
"CAS is an image-guided and minimally invasive method of vascular reconstruction," said Simon Yu Chun-ho, professor at the department of imaging and interventional radiology of Chinese University's faculty of medicine. "It's also a well-developed and mature technique."
From 2006 to last year, the faculty's department of medicine and therapeutics analysed images of the carotid arteries of 96 patients who had strokes after receiving radiotherapy to treat head and neck cancer.
Researchers compared the images with those of 115 patients who suffered strokes caused by atherosclerotic stenosis, or thickening of the artery wall.
The results showed that 54 per cent of the former group had both of their carotid arteries affected by stenosis, compared to 22 per cent in the latter group.
It also found that the former group was more likely to develop severe narrowing or complete closing of the arteries.
The department of imaging and interventional radiology performed CAS on 65 patients suffering from radiation-induced stenosis in 2006 and observed them for four years.
The operation was found to be successful in all cases, reducing the annual risk of ipsilateral stroke - stroke occurring on the same side as the blocked artery - to 1.2 per cent.
The treatment had a similar effectiveness on atherosclerotic stenosis, when arteries thicken because of a build-up of white blood cells, the study showed.
Chu Hom-wing, 50, who was at the release of the study yesterday, suffered from cancer in his nasopharynx - the uppermost region of the throat - and had radiotherapy in 2000.
Eleven years later, he suffered a blackout at the Man Kam To border crossing.
Doctors at the Prince of Wales Hospital, a teaching hospital of the Chinese University's faculty of medicine, found his left carotid artery was 90 per cent blocked, causing a stroke and paralysis in half of his body.
He underwent CAS at the time and had another operation last year when the supporting tube in the artery started to wear down.
"I couldn't move when I had the stroke, but now I can walk and move my limbs freely," said Chu, who is now preparing to become a part-time minibus driver.