Fast Safe Painless
These new, noninvasive medical tests don’t hurt a bit

BY DIANE PETERS

Thanks to the often dreadful nature of diagnostic tests, many of us are becoming experts at the art of procrastination. Who can be blamed for letting a colonoscopy slip to the bottom of their to-do list?

Fortunately, scientists have been devising a new generation of tests that don’t make you sick just thinking about them. As simple as a blood prick or computer calculation, these procedures offer a sneak preview of our medical future and help catch diseases before they begin to wreak havoc.

Here are three such tests, available in Canada now, plus a peek at some on the way.

Artery Reality
Heart disease is our number one killer, claiming more than 200 Canadians every day. The majority of heart attacks, blood clots and strokes can be blamed on blocked arteries.

A few years ago, retired surgeon Dr. John McCredie thought he might become a statistic. Something was wrong with his arteries, but no test could explain why he’d had a minor stroke in his 50s. At a checkup at the Shute Institute in London, Ont., a private clinic he’d frequented for years to get access to cutting-edge tests and treatments, doctors suggested checking his homocysteine levels. “I’d never heard of this blood test before,” recalls the well-read doctor.

Since the late 1990s, experts have agreed that high levels of this amino acid contribute to artery blockages that can cause aneurysms, heart attacks, strokes and blood clots. According to Dr. David Spence, director of the Stroke Prevention and Atherosclerosis Research Centre at the Robarts Research Institute in London, homocysteine levels between nine and 14 micromols per litre of blood are considered normal. People with levels over 20 have nine times the risk for heart attack, stroke and death compared with those with levels below nine. It’s a silent risk factor; about 20 percent of Canadians have high levels and few know it. But what’s different about this heart-disease marker is it’s easy to treat. Taking B6, B12 and folic acid supplements will normalize levels within months for most people.

“I expect homocysteine will become a more important risk factor than cholesterol,” says Spence. While the quick and reliable test is covered in many provinces, where it isn’t it typically costs in the range of $45.

McCredie’s homocysteine level proved to be an alarming 180. Spence immediately put him on vitamins, but after two years the level was only halved. So Spence prescribed betaine, a homocysteine-lowering supplement. With betaine and the B vitamins, his homocysteine level came down to seven. At 79, McCredie* had a homocysteine level of just 3, had had no more strokes, and his carotid arteries hadn’t worsened.

* Dr. John McCredie died of cancer in July 2003.

Screening Tests: Coming to a Doctor Near You Look for these diagnostic techniques to make your life safer soon Heart • Doctors rely on computed tomography (CT) scans to identify heart and artery problems. But an upgrade called electron beam computed tomography (EBCT), or Ultrafast CT, is five times faster. With the EBCT’s crisper images, doctors can see artery plaque and diagnose heart disease earlier. It’s available in the United States for about U.S. $300 per scan, and is approved for sale in Canada. • A low count of omega-3 fatty acids can put you at two to nine times the risk for heart disease or sudden fatal heart attack. Now an inexpensive test has been developed, which should soon be available to Canadians. “Most people need to improve their omega-3 score,” says Bruce Holub, a professor of nutritional sciences at the University of Guelph. Those scoring low can hike their levels by eating fish—particularly salmon, herring and mackerel—at least three times a week. Lungs Canadian doctors will soon be able to spot lung cancer before it’s incurable by using a computerized microscope to spot genetic changes in a patient’s sputum cells. “When we do a quantitative image analysis of the DNA in cells, we have a much better chance of catching people harbouring early lung cancer,” says Dr. Stephen Lam, head of the lung tumour group at the B.C. Cancer Agency and professor of medicine at the University of British Columbia. This test could be offered within five years. Ovaries Ovarian cancer’s early symptoms are pedestrian—loss of appetite, bloating, nausea—so only one in four cases is caught when the disease is highly treatable. In later stages, it kills up to 90 percent of its victims. Within the next few years, two new blood tests could change this. One checks for elevated levels of an acid; the other scans for certain proteins. In studies, the tests have proved to reveal ovarian cancer at the earliest stages. For more information, contact the National Ovarian Cancer Association at www.ovariancanada.org or telephone 877-413-7970. Skin Melanoma is so vicious that, once it has spread to organs, the survival rate is just five to ten percent. But it’s difficult to spot. “I can’t remember what a patient’s mole looks like from one year to the next,” says Dr. Kent Taylor, a Burlington dermatologist. “A picture is indisputably accurate.” He has the only MoleMax system in Canada. Using two digital cameras and computer software, it can map all the moles on a patient’s body and compare them, at 30 times magnification, with last year’s images. The high price tag ($45,000) for the system is keeping MoleMax from becoming widely available. D.P.

Mammogram Spell Check
Every year more than 20,000 Canadian women develop breast cancer and at least 5,000 die from the disease. But if the cancer is caught early, women have a greater than 90 percent chance of recovery. Along with self-examinations, mammograms are the best test for finding lumps before it’s too late. But mammograms—X-rays of the breast—are read by human eyes that can become tired. That’s why some Canadian doctors are looking to a new technology that takes a second look at mammograms to help catch even the tiniest lumps.

Computer aided detection (CAD) devices such as MammoReader and ImageChecker can pick up cancers on a mammogram so subtle they’re often missed. They are brand new in Canada and aious areas are highlighted, the image is returned to the radiologist, who combines her own observations with the CAD’s to make a diagnosis. In a study of 12,860 women published in Radiology, a CAD system found 20 percent more cancers than mammography alone. With all the controversy about mammograms, a CAD’s extra scrutiny is reassuring.

“It’s a big step, increasing by 20 percent the number of cancers we’re able to detect in the early stages,” says Dr. Linda Warren Burhenne, clinical professor in the Department of Radiology at the University of British Columbia. “It’s probably the most dramatic development since mammography.”

Recently, Dr. John Keyserlingk, who heads the Ville Marie Multidisciplinary Breast Centre in Montreal, used a regular digital mammogram to check the breasts of a 45-year-old patient who’d had available at a few medical centres in Montreal, Vancouver and soon in Toronto. For a cost to you of about $100—not always covered by private health insurance—the radiologist loads your mammogram into a scanner that digitizes the film. Then a computer combs every pixel for patterns suggesting calcifications or masses.

After suspic benign lump removed from her left breast eight months before. Radiologists thought the mammogram looked clean, but Keyserlingk checked it with the CAD—and found a seven-millimetre malignant tumour on her right breast. The woman got the tiny, dangerous tumour removed and radiation cured her cancer. Curious, Keyserlingk retrieved her original eight-month-old mammogram and fed it, too, through the CAD. Sure enough, the high-tech equipment found the malignant tumour when it was even more microscopic. “That’s what we’re asking the machine to do: pick things like this up a year earlier,” he says. That year can mean the difference between life and death.

Picture Imperfect? You don’t smoke (anymore), you exercise (sometimes), but still you wonder: Is there something growing inside that’s going to kill me? A new full-body scan promises to tell you just that. Relying on computerized tomography (CT), which is often used to photograph the heart, some doctors are offering this for the whole body to find early signs of heart disease, cancer and osteoporosis. Clinics in British Columbia and Alberta offer the service, and Ontario is expected to follow suit. “We want to find diseases that threaten people’s lives before they even know they have them,” says Dr. Stephen Valentine, codirector of Mayfair Diagnostics in Calgary. His clinic charges $1,100 for the scan, plus $800 for one that looks for colon cancer. But while the test sounds impressive, there are no long-term studies to demonstrate benefits or risks; in fact, in the United States, the American Cancer Society, the FDA and the American College of Radiology have officially criticized full-body scans. The test can give false positives, showing lumps that prove benign—after surgery. Equally troublesome, false negatives can miss problems that need attention; the patient might think he’s healthy and skip the tried-and-true tests. And remember, it gives you a dose of radiation. For those who still wish to try it, be sure to have the results interpreted by a reliable doctor, and take the film to your own physician. D.P.

Reaction Free
Up until Tyler Stinson was 11, he and his family led an extremely careful life. Any contact with milk, eggs, peanuts or shellfish would send him into life-threatening anaphylactic shock. He had to eat special meals, be watched constantly at his Aylmer, Que., school and live in a superclean house. Once, his older sister left a glass of milk on the table when Tyler was a toddler. He drank it, and the girl watched her brother go into shock and be taken to the hospital. She was never so careless again.

A year ago, Tyler’s doctor at the Montreal Children’s Hospital suggested running a sample of Tyler’s blood through a new test. Tyler hadn’t had a reaction in almost three years, so perhaps he’d outgrown his allergies.

Recently launched on the Canadian market, this blood test—called ImmunoCAP—was designed with kids like Tyler in mind: the one percent with dangerous food allergies. About ten to 20 percent of them are known to outgrow their allergies, but others may have difficulty finding out if they have, too, because in many cases it may be too dangerous to check using the standard skin-prick test. “If a patient has had a severe reaction to something before, a skin test could be risky,” says Dr. Donald Stark, a Vancouver allergist.

The ImmunoCAP test looks for certain allergy antibodies, and within days a numerical result is sent to your doctor, who compares it with a range for each allergen they’re testing for. Depending on your province, it is either covered or costs around $30 for each allergen tested. Any doctor in Canada, not just an allergist, can order the test. While it’s highly accurate for many common allergies, Stark says your doctor should also look at your allergy history to see if the results make sense. An allergist should then follow with an oral test in a medically controlled environment.

Tyler’s results showed he was no longer allergic to anything. Still, his mother, Kathie, admits, “I was hesitant.” So, under an allergist’s supervision, they slipped some milk into Tyler’s soy drink. He didn’t react. That day Kathie took Tyler to the grocery store and piled her cart with foods he’d never tasted. “It’s unbelievable,” she says. “He’s a totally different kid.” Tyler is more confident and takes more risks. He can now share his lunch, go to sleepovers and eat chocolate. Most important, he and his family don’t have to live in fear.

Medical Innovations on the Horizon BY JULIA SLATER Ever wonder what medical researchers will come up with next to diagnose or treat what ails you? Here’s a look at some exciting developments around the corner. Painless blood test for diabetics People with diabetes need to monitor their blood-sugar levels regularly to properly manage this disease. That means taking a blood sample by the “finger stick” method several times a day. The problem is that this can be uncomfortable and inconvenient, so many people simply don’t comply, increasing the risk of their having complications over the long term. Scientists have long been working to develop a reliable noninvasive blood test. And it looks like diabetics may have access to one in the near future. Researchers at the University of Texas Medical Branch in Galveston recently did a pilot study of one new technology, with promising results. The device they tested uses infrared light waves to get high-quality images of the tissues and an accurate measure of blood glucose. The technology is called optical coherence tomography (OCT). This may soon help the estimated 1.4 million Canadians with diabetes to live healthier lives, and avoid or delay the serious complications that often result from this disease. Stomach “pacemaker” to fight obesity Canadians are contending with some hefty weight issues these days. Statistics Canada reports that the number of obese adults grew by 24 percent between 1995 and 2001, meaning that 1 in 7 adults is considered obese. An alarming new Archives of Internal Medicine study of our neighbours to the south finds that 1 in 50 Americans is now “morbidly obese,” meaning that they are about 100 pounds overweight. That’s quadruple the number recorded in 1986. Some morbidly obese people opt for gastric bypass surgery, a radical procedure to reduce the size of their stomach. But this major surgery can cause complications. Now a safer alternative called “gastric stimulation” may offer hope for those in need of serious weight reduction. A doctor implants a battery-operated device —also known as a “tummy pacemaker”—under the patient’s abdominal skin in an outpatient laparoscopic procedure. The doctor programs the device to release electronic impulses to the stomach, which are subtle, but make the patient feel full sooner. The doctor can adjust the intensity of the impulses using a laptop computer and a remote-control wand. Patients "don’t feel buzzing or pain; they just don’t have an appetite or they get full very quickly,” said Dr. Scott Shikora, who has worked with the device, in an interview with Associated Press. The stimulator device has been tested on 450 obese people, who lost an average of 18 percent of their weight. The device was effective on two thirds of the subjects tested. Already on the market in Europe, it is still undergoing testing before it will be approved in North America. AIDS-prevention vaccine The AIDS pandemic has killed some 28 million people worldwide and infected 42 million more in the past two decades, the majority of the cases in Africa. Last year alone about five million people were infected with HIV. Given the failure so far at finding a drug to kill the virus, experts believe that developing a vaccine is the biggest hope to curb its deadly spread. Many drug companies are working on AIDS vaccines, approaching this challenge from different angles. Experts are more optimistic than they’ve been in the past, but say that there is still a long way to go. In July 2003 the first human test of a vaccine against the prevalent subtype of HIV in sub-Saharan Africa and Asia got started. The clinical trial is being held at sites in the United States and South Africa. This vaccine uses a copy of a small section of genetic material from HIV that is too small to actually reconstitute live HIV, so there is no danger of infecting the patient. In this first phase, scientists must determine if the vaccine produces serious side effects. They then hope to refine the vaccine “to the point that if an individual is subsequently exposed to HIV, they will be protected from disease,” says Dr. Robert E. Johnston, professor of microbiology and immunology and director of the Carolina Vaccine Institute. Sushi vaccines? Researchers at the University of Singapore announced in September that they have genetically modified zebra fish so that they produce the hepatitis B vaccine in their muscles. Still in the early stages of development, their next step will be to infect small mammals with the virus to see if the edible vaccine works. Edible vaccines have not been successful in the past because the animals and plants used did not produce enough protein. Zebra fish are very high in protein, according to the scientists involved. At some point, they will have to figure out how much of the fish humans would have to eat for the vaccine to be effective. But one thing is clear—the fish will have to be eaten raw, since cooking would destroy the vaccine.