Radiation from CT scans increases the risk of cancer

One of the best ways to combat unnecessary tests is to truthfully expose their risks and complications.

Patients can only make an informed decision after such a discussion with their physicians, and too often, the media ignores publicizing risk. If, for instance, more airtime was spent discussing the risks of breast cancer screening, the outcry wouldn’t have been as great.

Perhaps that’s changing.

The Archives of Internal Medicine recently released a study concluding that “roughly 72 million CT scans performed in the U.S. in 2007 will ultimately cause some 29,000 cases of cancer.”

That’s an attention grabber.

It was found that the amount of radiation given off by CT scans can vary by a factor of ten, based on the model of the scanner itself and the hospital the test was performed in. That makes it difficult to truly estimate a patient’s exposure.

Extrapolating their model to CT-angiography, a controversial heart scan that gaining popularity, it’s estimated that “one in 270 women who [receive the study] at age 40 will develop cancer as a result of the scan, and one in 600 men.”

That’s a huge number, and one that warrants discussion whenever the test is being considered. Let’s hope the media gives this as much attention as they do with their traditionally disproportionate reporting on a given test’s benefits.

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  • Micheál Breen

    I think the US seems to lag behind other jurisdictions when it comes to medical imaging and radiation protection. In Ireland, radiation protection forms an important part of radiographer and radiologist training. Investigations and interventions involving radiation exposure to the patient have to discussed between the referring physician and the performing radiologist and deemed justifiable. Even here though, I feel the patient is too far removed from this decision making process. When we ask patients to sign consent forms detailing 0.1% risk of organ failure from certain drugs, why are we not discussing the risk/benefits of ionizing radiation with them?

  • Anonymous

    I think the radiologist or radiology tech, should discuss these risks and get consent from the patients before preforming the tests. We do it for other procedures, why not for imaging procedures.

    Other options are making the MRI cheaper, so we can get MRI instead of CT, e.g. for the head.

  • Doc99

    The referring doc bears some responsibility here as well. It is far easier to check off a test on a referral form than it is to have an informed discussion.

  • Greg

    No decreases in CT use will occur if the doctors who order the tests are afraid that by not ordering it, they will expose themselves to litigation. Patients will have to be the ones who refuse scans themselves, allowing the doctor to write “CT discussed with patient, patient refused CT despite discussion of potential risks if not done,” decreasing the doctor’s liability.

    Radiologists don’t perform CTs, they read them once they are done. If malpractice rates in Ireland were even close to as high as they are here, radiologists would be loathe to dissuade a CT for fear of taking responsibility for not catching something.

  • Lorad

    Anonymous post #2,
    If you are going to ask patients to sign a consent form for radiology exams then shouldn’t that be done at the time of scheduling the appointment, before the patient takes time off from work and arrives at the hospital or imaging center?

    Also, even if you make MRI’s cheaper that doesn’t mean that it should be used more. Cost is not the primary reason that CT is ordered more often than MRI. There are some things that MRI cannot do as well as CT such as detecting calcifications and stones. MRIs still take much longer to perform due to the nature of the technology and physics. People with pacemakers still will not be able to have MRIs.

    Part of the problem with overuse of CT and other expensive tests such as MRI is that some people don’t know when ordering these exams is indicated.

  • Ray

    We have them fill forms even for a trivial procedures, so how come there is no discussion about risks despite having evidence of harm with these tests? There should some federal guidelines/ material that should be given to patients and family so they can make informed choices. I recently read an article where the parent( a surgeon) had to stop the ER doctor from getting more CT and xrays after his 12 yr daughter involved in trauma got 10-15 radiological studies during evaluation. Patients needs to be better educated and should be involved in decision making.

  • Josh

    I don’t know, 0.4% seems like a small number to worry about: a) there are bigger fish to fry, b) we don’t know what % of these cancers are clinically relevant (ie die w/ or from them), c) defensive medicine will continue to reign over common sense.

  • Rusty

    The risks and benefits of having radiation exposure could be discussed at the time of the patients scheduled appointment but don’t you think that the patient would want to know this before they take time off from work and show up for their appointment?

    Also, the cost of MRI is not the only reason that CT exams are ordered. In some cases CT exam is the better study than MRI. CT is much quicker and often easier tolerated by patients than MRI.

  • Rusty

    Agree with Doc99. It is not uncommon for a patient who is scheduled for a barium enema to be completely surprised when they are told that they are going to be given an enema. Their reply is that “my doctor didn’t tell me this.” Understandably many of these patients are upset that they were not informed about what they were scheduled for until they arrived at the hospital.

    The point is that some discussion about general risks of the radiology exams could be done at the doctors office. If the patient still has questions that require more detailed answers then they can call the Radiology department.

  • http://thehappyhospitalist.blogspot.com/2009/12/ct-scan-radiation-exposure-much-worse.html Happy Hospitalist

    Why not just put a big sign on the side of the CT scanner that says: CT SCANS CAUSE CANCER. Like they do with cigarettes. That way when patients are wheeled into the scanner room they have been informed.

  • ray

    Happy Hospitalist’s idea of labelling – “CT causes cancer ” on the machine may actually work. People who see it will discus it with family, friends and question their doctor for more info.

  • Michael

    I’m a little disappointed when I read posts like this, and some of the subsequent comments. I’m also concerned that the media will grasp on to this and make a big deal without all of the facts as we are prone to do.

    While it is true that there is a risk of cancer from ionizing radiation, the actually impact is still unknown. These estimates were calculated using 50 year old atomic bomb survivor data. However, at this point there has not been a connection between Medical radiation and cancer prevelation. In fact, as the number of CT scans has INCREASED, the prevelence of cancer has actually DECREASED.

    Additionally, according to a recent analysis by the U.S. National Bureau of Economic Research (Lichtenberg 2009), life expectancy increased more rapidly in states where the fraction of advanced diagnostic imaging procedures increased more rapidly,

    Again, I’m not arguing that diagnostic imaging, particularly CT, is overused (and I do agree with the liability concern statements). I am arguing that all of the details need to be included. It’s important to realize the benefits that come from these tests, as well as look at some of the risks.

  • Diora

    Michael – 1) have there really be enough years of follow up since the wide spread use (and overuse) of CT scans to claim that “to this point there has been no connection”? 2) at this point in time overuse is a bigger problem. How many people have you seen who really need CT scans and refuse it because they are afraid of radiation vs how many people get unnecessary CT scans.

    Just a few days ago I got another mailing from some local radiology lab trying to sell cardiac imaging tests to SYMPTOMLESS people with NO KNOWN HEART DISEASE or risks. The flyer included usual scare tactic description of nasty thing imaging tests can catch – one was aortic aneurism – as well as “who should get the test” section that mentioned “everyone over 50″. They had some special price for 3 tests. No mention of radiation, no mention that the tests aren’t really recommended by any medical organization, no mention of trivial things like one’s absolute risk. Now, I wonder what was it that caused this radiologists to send in this misleading and IMHO deceptive ad? Fear of lawsuits from patients they’ve never seen? Patients demands? I don’t think so.

    Now, you may argue that people who choose to believe this ad and get these tests are going to pay out of pocket and hence are free. True. But 1) most people don’t have knowledge to determine if the tests are needed 2) these tests have risks, but nobody bothers to tell it 3) these tests are likely to have false positives which will further drive up healthcare costs.

    FDA requires that prescription drugs advertising is accompanied by lists of side effects and risks. For some reason nobody objected on how these disclaimers would scare people away from necessary prescription drugs. Why don’t we have a similar requirement for tests? I think Happy Hospitalist has the right idea.

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