UROLOGISTS SHINE BLUE LIGHT ON CANCER
Treatment improves detection of malignant cells
Vancouver urologists are shining new light, literally, on cancerous bladder lesions, with a new tool that makes malignant cells appear pink when fluorescent blue light is shone on them. The conventional tool used to see malignant cells in the bladder is a white light camera-tipped instrument called a cystoscope that is passed through the urethra to the bladder.
But doctors say white light doesn’t always detect smaller, flatter cancerous lesions.
So Vancouver General Hospital and the University of B.C. Hospital have acquired a blue light cystoscope that is paired with a non-toxic, photosensitizing dye that illuminates abnormal cells.
An hour before the cystoscopy, nurses put the dye into a patient’s bladder through a catheter.
White light imaging is still used, but the blue light is recommended as an added feature in certain cystoscopy procedures.
“Things that we didn’t see before we can now visualize with blue light cystoscopy, which means fewer trips back to the operating room,” said Peter Black, a urology surgeon, scientist, and professor at UBC.
Black is one of a handful of surgeons at VGH and UBC hospitals trained to use the new drug-device combination. The technique is also coming soon to Surrey Memorial Hospital and Victoria General Hospital. A few hospitals in Ontario are the only other ones in Canada believed to be using the technology, but several other hospitals across Canada are evaluating it.
With the blue light, abnormal cells emit a bright pinky-red colour while normal cells appear a bluish green colour. Bladder cancer has a high rate of recurrence, so it’s important to remove as much malignant tissue as possible. A 2005 study showed up to 20 per cent of cancerous cells are missed with white light cystoscopy. Other studies have shown improved detection also leads to more appropriate adjuvant treatment such as chemotherapy or immunotherapy.
Health Canada approved the blue light technology about three years ago, but Black said surgeons in Europe have been using it for about a decade. The Canadian Agency for Drugs and Technologies in Health evaluated recent studies on blue light cystoscopy and found it appears to be associated with a reduced risk of recurrence compared with white light cystoscopy, but more long-term studies are needed.
The evidence is too thin to reach conclusions about whether fewer deaths will occur in patients whose tumours are removed with the new drug and imaging protocol. Information on potential harms is sparse, according to the agency.
Bladder cancer is the most common malignancy of the urinary tract and the fifth-most common cancer overall. It is also one of the most expensive cancers to treat because frequent diagnostic tests must be conducted during continuing surveillance, repeat surgical interventions and chemotherapy costs. Such monitoring is necessary because recurrence rates after initial treatment are as high as 60 to 70 per cent.
Surgeons remove the entire bladder in the worst cases, but when the bladder can be preserved, malignant pieces are removed.
Black said with the new approach, detection is so improved that chemotherapy may not be necessary. That helps make a better case for the capital cost of the $100,000 technology. Each time it is used on a patient, the cost for the dye and ancillary items is $700. But chemotherapy drugs cost the same, so if they can be avoided, the cost difference is nothing, he said.
Dennis Hovorka, a semi-retired financial planner, was diagnosed with bladder cancer two years ago and has already had four cystoscopies in which cancerous cells were removed. For his fifth, this week, Black told Hovorka he would use the blue light system. Hovorka said he was pleased with the idea he’d be getting the procedure.
“If getting this kind of technology will improve detection of cancerous cells, and make a difference, then I’m all for it. I had a cystoscopy earlier this year and Dr. Black said at the time he was not convinced that all the cancerous cells were removed. So I’m hopeful this time, with this technology, it is more successful.”