GUIDED BY THE GLOW
It’s a game changer for cancer treatment, says first surgeon in Canada to use it
Dr. John Sinclair is pioneering a new technique at The Ottawa Hospital using a drug that makes malignant brain tumours glow fluorescent pink and orange to guide his surgery. For local patients facing glioblastoma, it’s seen as a game-changer.
The patient was well medicated and frozen, but awake, as Ottawa neurosurgeon Dr. John Sinclair drilled carefully into his skull. When the drilling was done, a five by five centimetre piece of bone was removed revealing a brain tumour that glowed fluorescent orange and pink.
The surgery, performed last month at The Ottawa Hospital, was the first of its kind in Canada aside from clinical trials. A few hours before surgery, the patient had consumed a drink containing the drug 5-ALA (aminolevulinic acid). The drug concentrates within malignant glioma cells, causing them to become fluorescent under blue light.
The technique, called fluorescence-guided surgery, helps surgeons see malignant cells in patients’ brains, enabling them to remove more of their tumours. To Sinclair, who is pioneering the technique in Canada, it is a gamechanger.
“It is like being in a room with the lights dimmed and having the lights turned on. That is literally what it looks like.”
Sinclair operates on dozens of patients with primary brain tumours every year. Many of his patients have deadly glioblastoma multiforme, the most common primary brain tumour among people over 50. It is a devastating cancer, with a median survival rate of just 12 to 14 months with treatment. New treatments hold the promise of pushing up that survival rate by months or even years, but progress has been slow.
Without treatment — surgery, chemotherapy and radiation — patients survive just weeks.
What makes glioblastoma multiforme so deadly is, in part, the nature of the tumours. They don’t have distinct edges and grow like tentacles, making it almost impossible for surgeons to remove all of the cancer cells.
Traditionally, surgeons work with white light, a preoperative MRI scan to identify the tumour, and an intraoperative navigation system that functions like a car’s GPS system. As they do surgery and begin removing tissue, though, the MRI scan can no longer tell them what they are looking at in realtime and they must rely on their eyes, aided by a large operating microscope and eyepieces. It can be difficult to distinguish between brain tissue and tumour tissue.
Fluorescence-guided surgery brings malignant cells in sharp relief to normal brain tissue. The tumour glows a pink and orange colour and normal tissue doesn’t glow at all. It allows surgeons to act more aggressively to remove malignant cells because they can be more confident of what they are looking at.
In almost all cases, the cancer will return after surgery. The more surgeons remove, the better the patient’s prognosis.
Almost all of Sinclair’s brain tumour surgeries are done with the patient awake. During surgery the neurosurgeon stimulates the area around a tumour and asks the patient to perform tasks such as talking, looking at images and answering questions. This helps them to understand functional areas of the brain to avoid.
A technique developed by anesthesiologists at The Ottawa Hospital has allowed for longer surgeries in which the patient is awake. As a result, says Sinclair, “we probably do more awake surgery than any other centre in Canada.” The surgery can last up to seven hours, with physicians and surgeons interacting with the patient throughout.
The combination of awake surgery for primary brain tumours and fluorescence-guided surgery should make a difference in the survival rates of patients, some of whom will undergo two or more surgeries as the cancer recurs, Sinclair says.
Glioblastoma is relatively rare, but as the population ages there are more cases. There have been high-profile cases in the news recently. Tragically Hip frontman Gord Downie died last year of the disease. Former Ottawa MP Paul Dewar is currently being treated for it. U.S. Senator John McCain died from the cancer last month. Each has spoken publicly about the diagnosis.
“This has been an awful year for those patients and their families, but what it has done is brought attention to something that is a devastating disease,” which will help raise money for research and further advances to extend survival rates of patients, Sinclair said. “The courage that (Downie and Dewar) have shown by trying to help other people by making their stories known is immense with what they are facing.”
Fundraising has helped bring fluorescence-guided surgery to Canada. Through the Ottawa Regional Cancer Foundation, donors raised $15,000 for the first patients and more than $30,000 to support infrastructure. The drug 5-ALA, which is consumed orally by patients before surgery, costs between $2,000 and $4,000 a patient.
“We’ve been looking forward to this surgical approach being available in Ottawa for a long time,” said John Ouellete, vice-president of philanthropy at the cancer foundation. “We know it will be a complete game-changer for local patients facing brain cancer.”
Sinclair has spent the better part of two years preparing to bring the surgical technique to Ottawa. It has been practised in other parts of the world for years and is standard in Europe. The drug 5-ALA was approved by Health Canada in August, but is not yet funded by OHIP, which is why the Ottawa Regional Cancer Foundation is paying for the drugs and why fundraising for the new technique continues.
Sinclair would like to see fluorescence-guided surgery become standard in Canada. And, with leading research and techniques centred in Ottawa, Sinclair would like to have a brain tumour centre, similar to Toronto’s, based at The Ottawa Hospital, to offer patients quick, supportive and state-of-theart treatment.