Beware of sales pitch for unnecessary CT scans

May 15, 2009

I sometimes wonder if former prime minister Brian Mulroney still feels any pain.

Back in 2005, Mulroney received full-blown chest surgery after having undergone a "preventive" health screen. His surgery and subsequent re-hospitalization for complications came after what the media called a "routine CT lung scan."

What Mulroney probably wasn't told is that undergoing screening with high-tech CT (computed tomography) scanners might find all kinds of things lurking within our bodies, but those things will likely never go on to hurt us. Find a few "nodules" in the lungs and, without knowing if they are worth a worry or not, now comes biopsies, hospitalization, major chest surgery and, sometimes, death.

But guys like him are lucky, right? They found something that could have been cancer?

After a year researching this issue, I've come to the opposite conclusion: That preventive screening of healthy people to find cancer is not only wrong-headed but leads to way more over-diagnosis and over-treatment, disability, pain and death. Mulroney didn't have to go through what he went through.

Don't believe me? Maybe believe the data. Over the past year we examined the phenomenon of CT and PET (positron emission tomography) screening of hearts, lungs and full bodies -- screenings offered as "perks" to executives, and heavily advertised in Canada.

We interviewed more than 20 experts, analyzed the media reporting and marketing of these screening tests and conducted a nation-wide public opinion survey to see if Canadian consumers know anything about the benefits and harms associated with such screening.

Our research uncovered some incredible nuggets.

We found that private clinics selling such screening tests can essentially make whatever claims they want (one ad said, "A full body scan can save your life") and that Health Canada does not ban advertising, as it does with prescription drug advertising.

We also found that the practice of searching for cancers in healthy people with high-tech imaging equipment more often than not will find harmless abnormalities (as it did in Mulroney's case) and these discoveries lead to more surgery, more hospitalizations and sometimes complications, all to be dealt with by the public health care system.

On the question of whether these screening tests actually find cancers, the largest study on CT-based screening for lung cancer found that the screen identified cancers in only 1.3 per cent of participants, yet the tests detected abnormalities 10 times as often for things that were benign. That's a lot of unnecessary pain to the individual and cost to the system.

Are these screens safe? Half the Canadians we surveyed said a CT scan delivered "the same" or "less" radiation as a conventional chest X-ray. In fact, a CT scan can deliver the equivalent of about 500 chest X-rays. I don't know if this is a problem, but being exposed unnecessarily to radiation is always a worry, a fact confirmed last month by a Harvard study that said CT screening might be causing up to 1.5 per cent of all cancers in the U.S.

The act of screening for cancers could actually cause them.

Does anyone care? Perhaps the biggest shocker was the discovery that Health Canada and provincial ministries of health are not worried about the intemperate use of screening by the worried well. In their defence, they point to the professionals -- the radiologists. They call the operation of a CT scanner a "practice of medicine" issue. It's as if they say, "we may approve the sale of scalpels in Canada, but we don't tell surgeons how to use them."

Fair enough. Yet even though the Canadian Association of Radiologists only urges evidence-based screening, we found no data that it is punishing those who are delivering these scan scams.

While we would all argue for the appropriate use of CT scanners to diagnose and treat cardiac or cancer patients, the selling of heart, lung or full body scans to healthy individuals is an expensive, high-tech hunting expedition that puts more patients into an overburdened public system where they can face surgical disability, possibly death and lingering pain.

As for the pain, I'm still wondering about a former prime minister.


Alan Cassels is a drug policy researcher at the University of Victoria and author, along with Jaclyn van Wiltenburg and Wendy Armstrong, of "What's in a Scan: How Well Are Consumers Informed About the Benefits and Harms Related to Screening Technology (CT and PET Scans) in Canada?" You can download their report at: <> .