Pamela FayermanVancouver Sun
Thursday, April 23, 2009
Health consumers are largely naive about radiation and other risks that come with full-body and other screening tests marketed by private clinics, a University of Victoria health policy researcher says.
Alan Cassels, co-author of a recent report published by the Canadian Centre for Policy Alternatives, said people seem to think early detection of any disease is safe and always a good thing if it is under the guise of so-called preventive medicine.
"But offering for sale [for up to $2,500] heart, lung or full-body scans to healthy people with no symptoms is questionable, controversial, unregulated and not even recommended by professional associations of radiologists," he said.
Apart from radiation exposure, people can receive false positive findings and then be subjected to further medical tests that are usually done in the public medicare system.
It is estimated that for every 100 people who have a full-body CT scan, 30 to 80 will be told about an anomaly that needs further, sometimes invasive, investigation but that turns out to be a false alarm, said the report.
CT exams provide detailed images of internal organs and help doctors make diagnoses and guide medical treatment decisions. But they expose patients to a higher radiation dose than most other imaging tests such as plain X-rays. No one in Canada collects data on the number of scans done in the private system.
The Canadian Cancer Society suggests there are only three tests with sufficient evidence to warrant screening of people with no symptoms; for breast, colorectal and cervical cancers, none of which involve CT scans. Health Canada recommends against full-body CT scans in healthy people, as does the FDA in the U.S.
Cassels' report looked at how well Canadian consumers are informed about the benefits and harms of screening technology such as CT and PET scans.
Part of the report refers to a survey of 400 Canadians. Of those, 10 per cent said that even though they had no symptoms, they had paid privately for a CT scan of their lungs, heart, colon or whole body, just to find out if they had any problems.
The survey also revealed:
- 40 per cent have heard about private screening tests through the media or ads.
- 65 per cent said they thought if a scan detected a potential problem, the person would be more likely to live longer.
- Respondents said they would rather receive a free full-body CT scan than a $1,000 cheque.
- Two-thirds of respondents said they didn't believe there were any risks related to CT scans, or didn't know about them.
- Only 18 per cent of respondents correctly stated that CT scans had more radiation than conventional X-rays; nearly a third wrongly thought there was less.
According to the Canadian Institutes of Health Information, the number of private clinics in Canada with CT scanners increased from two in 2000 to 21 in 2007 (including about six in B.C.)
"Canadian consumers are generally misinformed about the reliability and safety of different screening tests and lack access to effective, consumer-oriented guidance around these screening procedures," the report says.
A recent article in The Medical Post, a publication primarily for doctors, stated that one CT of the heart was equivalent to about 600 chest X-rays.
Radiation dose from imaging equipment is measured in millisieverts (mSv). A CT of the heart exposes an individual to an estimated radiation dose of 12 mSv.
A Vancouver resident has an estimated background radiation of about 2.5 mSv in a year.
In this month's journal Radiology, Boston researchers said patients who have many CT scans in their lifetime may be at increased risk for cancer from the accumulated exposure to radiation.
Cassels said it is appropriate to use such diagnostic tools on those at high risk of diseases or to diagnose and treat those with suspected or diagnosed cancer or other suspected or diagnosed diseases.
But with the advent of corporate or private pay "executive health checkup programs" the use of such high-tech screening is growing and should be regulated.
"It is clear the information consumers receive from the proponents of such tests is often unbalanced, exaggerating the effectiveness of the screening and downplaying or avoiding discussion of any potential harms," the study states.
Sun Health Issues reporter
After reading this would you rush to a private clinic? Thoughts?