Medical Advances: That May Save Your Life
A new generation of treatments has joined the fight against stroke, cancer and heart disease
Jocelyn Lahaie, a 40-year-old computer consultant and soon-to-be first-time father, reached for a box of breakfast cereal on June 16, 2000—Father’s Day—and collapsed, the victim of a stroke. The paralysis that seized the left side of his body was accompanied by the fear that he would never be able to work again and provide for the baby due in five months. “If he had remained in that state, he would have been severely disabled,” says Dr. Andrew Demchuk, the neurologist who treated Lahaie in the emergency room at Foothills Medical Centre in Calgary.
Once doctors had done a CT scan and found a blood clot in one of Lahaie’s brain arteries, they infused him with the clot-busting drug tPA (tissue plasminogen activator). But they couldn’t tell if the artery was opening up, so the physicians used a state-of-the-art diagnostic tool to keep their eyes on the clot. It showed that blood was not yet flowing through the artery: They would have to try a more aggressive treatment.
Since it had already been two hours since Lahaie’s collapse, doctors knew they were losing precious time. So they opted for an experimental procedure. They ran a catheter up Lahaie’s femoral artery and into the brain, then injected a small amount of tPA right into the blocked artery. “The clot broke up,” says Demchuk, “and within minutes he popped up his left arm and could move it well. It was truly a Father’s Day miracle.” Today Lahaie is fully recovered.
Lahaie’s case is just one example of how medical innovations are giving doctors powerful new ways to combat serious disease.
Here’s a look at some promising advances in the treatment of stroke, cancer and heart disease. A number of these marvels are available right now, and others may be just around the corner.
Real-Time Monitoring. Strokes cause brain cells to die off—and are the fourth leading cause of death in Canada and a major cause of disability. To monitor the status of the clot in Lahaie’s brain, his doctors used the latest generation of Power M-mode transcranial Doppler (TCD), a device that lets physicians see if the intravenous tPA is working. Power M-mode TCD shows an image of the blood clot in real time—doctors can see if the clot is dissolving. The screen is about the size of a laptop monitor, so it can be pulled right up to a patient’s bedside and give immediate, continuous feedback.
How it works: A Power M-mode TCD is a noninvasive ultrasound device that sends sound waves through the skull. The waves hit the red blood cells in the brain’s vessels and bounce back to the device. Depending on the speed and direction of those red blood cells, it can tell if the arteries are open, if blood is flowing, how fast it’s moving and in which direction.
Is it available? Foothills Medical Centre, the University of Alberta Hospital in Edmonton and St. Michael’s Hospital in Toronto have Power M-mode TCD technology, and other centres are considering it. As soon as more doctors and nurses are trained in it, its use could become widespread, especially since it is relatively inexpensive.
“When people hear a diagnosis of cancer, they are terribly frightened,” says Dr. Joseph Connors, head of the Lymphoma Tumour Group at B.C. Cancer Agency and a professor of clinical oncology at the University of British Columbia. “But the problem of cancer is being tackled in small steps, and over time, those steps are gradually having an impact. Hundreds of clinical trials are happening all over the world to test effective new therapies.”
Here are two of these new weapons:
Targeting Rays. One of the most effective ways to kill cancer is with radiation. The problem, though, is that traditional radiation strikes not only cancerous cells but also the surrounding noncancerous tissue, and it can cause side effects ranging from nausea to organ damage and even paralysis.
A new, more exact method called intensity modulated radiation therapy (IMRT) concentrates rays more precisely on the target, allowing doctors to deliver higher doses with fewer side effects.
How it works: Instead of hitting a tumour with large beams of radiation from only a few directions, as is done with conventional radiotherapy, IMRT calculates precise angles and doses using a computer. Then it fires about 120 small beams at the tumour from many directions as it rotates around the patient. The exact dimensions and location of the tumour are first verified by CT scan and magnetic resonance imaging (MRI), which also identify the healthy surrounding tissue. IMRT’s accurate targeting allows delivery of higher doses of radiation. “And that,” says Dr. Gino B. Fallone, director of medical physics at Edmonton’s Cross Cancer Institute (CCI), “allows you to kill more cancer cells.”
Is it available? IMRT has been available in Canada since the CCI started treating the first patients with it in April 2000. It is also available at Princess Margaret Hospital and Sunnybrook & Women’s College Health Sciences Centre in Toronto, and at McGill University Health Centre in Montreal, among others. Consult your physician for locations nearest you.
Smart Bombs. The body’s immune system normally produces antibodies to help fight infection. Now similar antibodies, called monoclonal antibodies, can be made in the laboratory and used in a variety of ways to attack cancer with great accuracy.
Because monoclonal antibodies are so new, their long-term impact on survival won’t be known for several years. But the research so far has been extremely promising. “They have fewer side effects than chemotherapy drugs,” says the B.C. Cancer Agency’s Connors. “And that can be a real boon to the elderly and others too frail to undergo standard treatment.” A recent study of the monoclonal drug rituximab has also shown that combining it with standard chemotherapy can improve the cure rate for certain types of non-Hodgkin’s lymphoma.
How it works: Chemotherapy, in a sense, is like dropping a bomb on a cancer tumour. It injures normal cells while killing cancerous ones, and that damage is why patients receiving it so often suffer from nausea, hair loss and other side effects.
Monoclonal antibodies, by contrast, act like “biological missiles,” zeroing in on cancer cells and launching a variety of attacks—delivering drugs or toxins, for example, or triggering an immune reaction. And because they cause less damage to normal cells, monoclonals fight cancer without making people so sick.
Connors cites the case of a 27-year-old woman who was diagnosed with a large lymphoma on her right kidney and within her chest. Connors and his colleagues treated her with two courses of both chemotherapy and radiation, but the tumour returned after each treatment —and then another tumour developed near her ear. “Ordinarily, at that point we’d have assumed that she would die from the disease,” Connors says. But then doctors were able to give the woman the monoclonal rituximab as soon as it received approval. The result? She has been tumour-free for more than a year.
Is it available? Health Canada has approved two monoclonals: Herceptin, for women with metastatic breast cancer whose tumour cells have too much HER-2 protein, and rituximab, for treating a type of non-Hodgkin’s lymphoma.
Robotics-Assisted Heart Surgery. When an artery in the heart is blocked, doctors usually perform bypass surgery to reroute blood along a new path near the clogged one. The procedure saves lives, but the patient wakes up in considerable pain, spends days in intensive care and needs months to recover.
Now a method being pioneered in London, Ont., may make this scenario a thing of the past. Dr. Douglas Boyd, director of the National Centre for Advanced Surgery and Robotics at London Health Sciences Centre, is performing robotics-assisted closed-chest bypass surgery on the beating heart. The technique makes it unnecessary to cut open the chest, saw through the breastbone, force the rib cage apart and stop the heart—all required in conventional bypass surgery.
How it works: The doctor makes about four tiny holes, or “ports,” in the patient’s chest, then sits at a nearby console and controls the movements of three robotic arms. One holds an endoscopic camera that shows the surgeon the interior of the patient’s chest cavity. The other two manipulate tiny surgical instruments, none more than five millimetres in diameter. Since the robotic arms are steadier than human hands, they can work on a beating heart, eliminating the need for a heart-lung machine. The patient wakes up in considerably less pain and can be back at work in weeks.
Is it available? Boyd and his team performed the world’s first closed-chest beating-heart robotics-assisted bypass operation in September 1999. Since then, they have done single-artery bypasses on more than 80 patients. Once they receive approval, expected next year, they hope to perform multivessel bypasses as well. The procedure is not available at any other centres.
The system, called ZEUS, costs about $1.5 million, and heart surgeons are still being trained on how to use it. Boyd predicts that robotics systems will become more mainstream as computing power increases and that cardiac surgery generally will become less invasive over the next decade.