A Game-Changing Statistic: 1 in 250

Bob Wachter

Although the medical profession has been harming unlucky patients for centuries, the patient safety movement didn’t take flight until 1999, when the Institute of Medicine published its seminal report, To Err is Human. And that report would have ended up as just another doorstop if not for its estimate that 44,000-98,000 Americans each year die from medical mistakes, the equivalent of a jumbo jet crashing each day.

Come to think of it, the quality movement also gelled after the publication of Beth McGlynn’s 2003 NEJM study, which produced its own statistical blockbuster: American medical care comports with evidence-based practice 54% of the time, a number close enough to a coin flip to be unforgettably disturbing.

These two examples demonstrate the unique power of a memorable statistic to catalyze a movement.

Last month, my colleague Rebecca Smith-Bindman, professor of radiology, epidemiology, and ob/gyn at UCSF and one of the nation’s experts in the risks of radiographs, gave Medical Grand Rounds at UCSF. Her talk was brimming with amazing statistics, but this is the one that took my breath away:

A 20-year old woman who gets an abdominal-pelvic CT scan (i.e., just about any young woman coming to the ED with belly pain) has a 1 in 250 chance of getting cancer from that single scan.

Did that fully register? One CAT scan, which until recently most of us ordered with no more restraint than we exhibit when asking the Starbucks barista for a tall latte, will cause cancer in one out of every 250 patients. Two-hundred fifty: that’s the number of students in my college Bio 101 class. Wow.

This is particularly scary given the remarkable increase in the use of this technology. Get this:

  • Three million CT scans were performed in the U.S. in 1980. In 2011, there will be 72 million, an average of 19,500 every day.
  • One in five Americans will receive a CT scan in any given year; some experts suggest that at least one-third of those scans are unnecessary.
  • Between 2000 and 2005, Medicare spending for imaging studies more than doubled, from $6.6 billion to $13.7 billion, twice the rate of growth of physician fees.

And, although none of these examples has quite the impact of the 1-in-250 statistic, there are lots of other scary risk data, such as:

  • The best estimates are that radiation from CT scans causes 29,000 excess cancers each year in the U.S., mostly in women.
  • Researchers estimate that 15,000 people will die from the direct effects of the 72 million CT scans performed in 2007 alone.
  • A 2004 study found that less than 50 percent of radiologists, and 9 percent of ER docs, were aware that CT scans could increase the subsequent risk of cancer.
  • A multiphase abdominal/pelvic CT scan has the same radiation wallop as 500 transcontinental flights, 450 chest radiographs, and 74 mammograms.
  • And those airport body scanners you’ve been so worried about? You’d need to be scanned 200,000 times in order to accumulate the radiation that you get from a single CT scan. I’m a 1K United flyer, but I won’t close in on 200,000 scans for the next couple of centuries.

In her grand rounds, Rebecca walked us through the multiple lines of evidence on the risks of radiation from CT scans, particularly those drawn from studies of Japanese A-bomb survivors and individuals who received radiation for both malignant (i.e., lymphoma) and non-malignant (i.e., acne) disease. All pointed to the conclusion that doses in the range of those delivered by CT scans are fully capable of causing cancer.

Remarkably, with all the attention given to regulating food and drugs, the radiation delivered by CT scanners has gone largely unregulated. (If you ask me, I’d rather receive a precise and predictable dose of radiation than of Vitamin D or Azithromycin.) Rebecca found that CT scanners at four Bay area hospitals delivered radiation doses 66% higher than the usually-quoted doses, and that there were staggering variations (up to 13-fold) among different scanners performing precisely the same test. In her talk, she blamed the lax regulations on radiation physicists, fastidious types who have been reluctant to take a stand on maximum radiation doses since they can’t define those doses precisely.

While I’m sure that’s true, I have to believe that some of the reluctance to blow the whistle can be traced to the usual Medical-Industrial Complex: scanning equipment manufacturers, radiologists, and hospitals who have no particular interest in killing this particular egg-laying goose. If you doubt that these forces are at play, witness the billboards for $1000 total body scans that line Florida’s highways (scans that, when performed in healthy people searching for asymptomatic tumors, undoubtedly cause more cancers than they cure). Even now, despite powerful evidence of the risks, there are some in the radiology community who don’t find the science compelling enough to alter their practice. The parallels to the Global Warming debate are eerie, and troubling.

Even if the risks turn out to be less than we fear, most skeptics now agree that we’re causing a lot of cancers, and that many could be prevented if we took a few sensible steps. Manufacturers, hospitals, and radiology facilities should test the radiation exposure of their scanners, with the goal of decreasing the variation and delivering the minimum dose that creates an acceptable image. Ultrasounds should be substituted for CTs when possible, such as in follow-up of patients with documented kidney stones. There is evidence from Mass General that the use of computerized appropriateness protocols can markedly cut down on the number of CT scans, and thus the cancer risk. And, if we need to obtain the patient’s informed consent before transfusing a unit of blood, we should also do so before ordering a CT scan, since the latter is a far riskier procedure.

But changing culture will be more important, and harder, than changing protocols. We physicians have become so accustomed to saying “Get the scan” that we have turned our brains off. Several months ago, I cared for a woman with a painful lumbar compression fracture of unknown duration. We asked the orthopedic surgery service to see her in consultation, and the resident’s recommendation – made without a hint of self-awareness or irony – was that we obtain both a CT and an MRI. I was dumbfounded. Yes, each test can provide slightly different information, but I don’t believe that both were absolutely necessary; nor did a couple of experts I later spoke with. (We ended up getting the MRI only, which produced all the information we needed.) Somehow, we must find a way to break our reflexive radiographic profligacy.

As we struggle as a nation to “bend the cost curve” and we grapple with the nexus of low yield and expensive medicine (the dreaded “R word”), let us all agree that when we have an issue like this – an overused technology that harms or kills thousands of patients each year – we come together to do the right thing. CT scans can be immensely helpful, even miraculous, at times, but there is no question that the right thing is to Just Say No far more often than we ever have before.

Robert Wachter, MD, is widely regarded as a leading figure in the modern patient safety movement. Together with Dr. Lee Goldman, he coined the term “hospitalist” in an influential 1996 essay in The New England Journal of Medicine. His most recent book, Understanding Patient Safety, (McGraw-Hill, 2008) examines the factors that have contributed to what is often described as “an epidemic” facing American hospitals. His posts appear semi-regularly on THCB and on his own blog, Wachter’s World.

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  1. My name is MAJ Rob Klingensmith and currently am currently a student at Intermediate Level Education (ILE); Command and General Staff School, Ft. Gordon, GA.

    About 8 years ago, I was a fairly new Family Nurse Practitioner. I remember a very nice Radiologist, Ann, who was always willing to discuss films, results, and do a bit of teaching. We had conversation about this particular topic, how much harm is being done by the amount of radiation we expose our patients to when ordering CT films, CXRs, etc. She had mentioned that this topic was beginning to be a big focus in the world of Radiology, and that we are seeing the affect of increased cancers today because of the amount of scans we do.

    I never forgot that conversation, and luckily, it was at the beginning of my practice years. I still order CT scans- when I have to. If I’m suspicious of a patient having renal stones, I opt for Ultrasound rather than moving to CT. Or sometimes I will take a gamble and just get a regular flat abdominal series to rule out if there is a stone present or not; although, I’ve had little success over the years of actually seeing stones on flat films because of the lack of sensitivity- usually from overlying obstructive bowel patterns or obesity of the patient- however, taking a chance on one plain film in a non-urgent case I feel is worth it, especially when I can get the film and the results that very same day.

    Since I work in Family Practice, the need for stat or asap CT films is rarely indicated, but because of the amount of chief complaints we see for non-specific abdominal pain (along with ruling out renal stones if plain films or US is non-diagnostic), this is probably one of the big reasons we will get CT imaging. But what amazes me, or perhaps concerning, are patients who have a long track history of provider and ER shopping for their undiagnosed abdominal pain (or other problems). Some of these patients have had up to 10 CT studies over the past several years. And now, they sit in your office looking ill for belly pain that is still yet elusive. I think we all have been here, and unfortunately we are still increasingly having to practice defensive medicine; because you do not want to be that one provider who didn’t order the CT scan that would have shown a lower abdominal aorta aneurysm or other urgent problem(and most likely nothing to do with the past several years of abdominal pain).

    I certainly don’t know what the answer is, other than trying to be more judicious when having to order imaging studies. And perhaps trying to educate our patients who request (or expect) us to order them CT studies that this is not always the best choice.

    MAJ Rob Klingensmith, FNP-BC

  2. i even have a friend where his cousin died because of doctor’s wrong diagnosis. she gets too many radiation exposure during the time when her body is weak. it leads to cancer…sad, but alot of cases are like this!

  3. If any people die from medical mistake it not intentional.But sometime doctors become so creepy.They don’t provide proper treatment as long as they are not earn enough money from the patient.It can lead a patient to death.I just want to say profession of doctor is not all about business but humanity. They should maintain these humanity to their patient.

  4. This is an amazing statistic – “44,000-98,000 Americans each year die from medical mistakes, the equivalent of a jumbo jet crashing each day.”

    I believe I’ve also read that the pharmaceutical side effects are the #4 cause of death for older adults. Just think of the celebs who have died from prescription drug abuse or overdue or mixing

  5. i even have a friend where his cousin died because of doctor’s wrong diagnosis. she gets too many radiation exposure during the time when her body is weak. it leads to cancer…sad, but alot of cases are like this!

  6. Thanks for the great article. I think that huge proportion of the public are completely uninformed about topics like this which is pretty scary. I guess that when normal everyday people visit their doctor and he/she suggests something like a scan that seems so routine that they just do it without thinking about the consequences…….I think that most people don’t even realize that there are consequences.

  7. Technology will keep up with the needs of patients. It is just that in a slow economy the resources are cut just when they are needed the most.

  8. As long as lawyers are dictating medical practice, there will always be unneccessary CT scans just because somebody bumped his/her head and went into the ER get into medical school or even enrolled must be made aware of this because too many doctors have accepted the status quo. Thanks for sharing, radiation awareness must be increased.

  9. hi ive had 5 ctscan and im only 28 so does this mean im going to get cancer from this

  10. What are the other options. Sure you have Ultrasound, but is that realistic in this situation. I sure hope technology can keep up with the needs of our patients.

  11. Thank you for bring attention to this important topic. A major problem is that frequently patients end up having multiple procedures that involve radiation exposure over a relatively short period of time. For instance, a patient may undergo a CT angiogram, nuclear perfusion test, and a coronary stenting with flouroscopy all in a short period of time. It seems that there is not that much emphasis on limiting radiation exposure during the test by using imaging protocols that are designed to limit exposure as opposed to just maximizing image quality.

  12. Obviously, if there is no alternative, one should indeed opt for the more “invasive” CT scan.
    However, medical companies keep cranking out safer and less invasive methods for diagnosing and treating cancerous growths.
    Let’s just hope that modern medicine continues to improve.

  13. As long as it is considered malpractice to remove a normal appendix without a CT scan there will be CT scans. I would hope ultrasound could replace many of the CT’s, at least for appendicitis. That is not presently available as a modality for appendicitis at my hospital, nor is it standard of care to do an ultrasound.

    But ther are many CTs done for appendicitis that show a seperate surgical problem or show Crohn’s disease. Ultrasound will miss those.

  14. I’m surprised Bob Wachter has fallen into the trap of “IOM medical mistakes = doctor mistakes”

    The 98k figure cited by the IOM study involved ALL medical errors, not just those by doctors. That includes nurses who gave the wrong med; pharmacists who miscalculated chemo agents; physicists who programmed the wrong radiation dose into the computer, etc.

    Doctors are not the only people making mistakes out there.

  15. There are two other sides to CT scan use: 1) patient expectations; and 2) fear of tort reprisal. Patients have come to expect a CT and MRI scans as the standard of care, and should anything go wrong or a diagnosis be missed, doctors can envision a courtroom lawyer asking, “Why didn’t you order a scan, doctor?”

  16. Dr. Wachter makes some good points but we on the front lines are receiving mixed messages from the MGH. Wachter says the MGH has protocols to cut down on the use of CT scans but their radiologists might not have received the message. They just published a paper in AJR (discussed in my blog http://is.gd/CbjyoU) stating that in a study of 584 ED patients with abdominal pain, abdominopelvic CT scans changed the treatment plan in 42%.

    My experience is that the public wants an accurate diagnosis. Just this past weekend, I was consulted on two young women with abdominal pain who the ED MDs were certain had appendicitis. I of course was limited in my ability to examine them because they received narcotic pain medication. CT scans revealed no appendicitis and both patients were sent home without surgery.

  17. This kind of information is important for all healthcare professionals and patients to know. But in my mind, I see one of the many news shows running this information as one of the many negative shows aimed at the medical field. Medical professionals have to be as aware of their professions ‘issues’ more than anyone. Because when laypersons read information such as this, the majority of them are going to believe that they have been exposed to possible Cancer. Why? Because many individuals have had CT scans or been in an area of a healthcare facility that does CT scans. The health care professionals are just as in danger as the lay persons regarding excess radiation. Still, the better health care professionals get at knowing and disseminating their professions ‘concerns’ to the public, the more trusted and careful they will become. And the opportunity for negative stories will be decreased.

  18. Great work Bob. And not to mention that as Shannon Brownlee showed in her great book Overtreated all those CT scans dont actually make any difference to the accuracy of diagnosis!

    But of course we’ve already shown that stents dont cure heart disease in the COURAGE trial, and we put in more now than we did then. No way is a minor study like Rebecca’s going to stop the radiological-industrial complex in its tracks.

  19. While the need to monitor and control medical radiation exposure is not disputed, the veracity of oft-quoted risk estimates for cancer induction from low levels (<100 mSv) of low linear energy transfer (low-LET) ionizing radiation, such as x-rays and gamma rays, is unknown. These estimates for cancer induction from low-dose radiation stem from the Biologic Effects of Ionizing Radiation (BEIR) VII report and presume the linear, no-threshold (LNT) hypothesis – that cancer risk increases in a linear fashion from low to high doses, and there is no dose below which a risk does not exist (1). Basically, the world is divided into 3 groups:

    1. Those who believe the LNT hypothesis.
    2. Those who don't know but choose to practice in a manner that leaves open the possibility that low levels of low-LET radiation may cause cancer.
    3. Those who don't believe the LNT hypothesis.

    The LNT hypothesis for cancer risk from low-dose medical imaging has been debated for years, without conclusion (2), and a direct, causal link between computed tomography and cancer induction has not been demonstrated (1). Based on observations made in atomic bomb survivors, the theoretical risk of a fatal cancer from a 10 mSv CT scan has been estimated at 0.05% (1 in 2000) (3). This low but finite risk estimate is mirrored in a large study of British radiation workers (4), but a clear-cut risk in the low dose range (<100 mSv) is only suggested if one uses the LNT hypothesis to fit the data (1). Without this presumption, the risk of cancer in this low-dose range is uncertain. Moreover, the risk estimates from atomic bomb survivors have not been translated unequivocally to the risk from medical imaging, owing to a number of confounding co-variables, including the type and flux of radiation, and the age and co-morbidity of the affected population (5).

    There is a strong biologic counterargument to the notion that low levels of low-LET radiation are carcinogenic (2, 5). Tubiana et al (5) report, “there is no evidence of a carcinogenic effect for acute irradiation at doses less than 100 mSv and for protracted irradiation at doses less than 500 mSv.” As these radiation doses are grossly in excess of doses delivered with a single 10 mSv CT scan, it is imprudent for those in group 1 to base medical decision-making solely on these risk estimates. Rather, practitioners should operate under the premise of group 2. As Smith-Bindman advocates (6), “we must ensure that patients undergoing CT receive the minimum radiation dose possible to produce a medical benefit.” One of the best ways of reducing radiation is to assure the appropriateness of the ordered test and to eliminate tests that are not indicated. Of greatest concern is the possibility that patients in need of medical imaging may be denied the benefits of modern health care owing to an unproven and uncertain risk of cancer.

    1. McCollough CH, Guimaraes L, Fletcher JG. In defense of body CT. AJR 2009;194:28-39.
    2. Charles MW. LNT – an apparent rather than a real controversy? J. Radiol. Prot. 2006;26:325–329.
    3. http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsand Procedures/MedicalImaging/MedicalX-Rays/ucm115329.htm (accessed on 11/21/10)
    4. Muirhead CR, O’Hagan, JA, Haylock RG, et al. Mortality and cancer incidence following occupational radiation exposure: third analysis of the National Registry for Radiation Workers.Br J Cancer 2009; 100: 206–212.
    5. Tubiana M, Feinendegen LE, Yang C, Kaminski JM. The linear no-threshold relationship is inconsistent with radiation biologic and experimental data. Radiology 2009;251:13–22
    6. Smith-Bindman R. Is computed tomography safe? NEJM 2010;363:1-4

    James A. Brink, MD
    Chair, Commission on Body Imaging
    American College of Radiology

  20. Patient Safety is no longer a empty gesture of the Medical Community to Ignore. Hospital Acquired Infection are Preventable and those who serve purposely ignore CDC Protocols. Spreading infections like any three year old that did not know any better. However,These Doctors and the Institutions;”K now Better!” Poor, unluckly patients who number 90,000 plus who die from these complications from Preventable Hospital Acquired infections and another 90,000 plus each year ,die from Medical Errors. The actual numbers of deaths are vastly played down and often burried or excluded from view.
    It may seem easy to claim that the patient was unlucky from the Medical Profession’s point of view. Actually,its not luck that increases a persons chance of Infection and Medical errors. It is the failure of the Medical Profession to subscribe to proven Protocols and the blinding arrogance that insists they Know Better. The other factor is the win ,win premise of a paycheck regardless of outcomes.
    Advocacy comes from protecting ones self and others from institutions that places profitability above patient safety. Those who willfully ignore enforcement of hand washing and often chuckle at the concerns of imformed patients. Its the advocates pledge to do all they can to prevent any further needless deaths.
    As being unlucky well it seems that is a pleasant way to say to bad,so sad. Now about the Bill!

  21. I think informed consent is possible but only of public starts more aggressively educating themselves. In fact, I think a lot of the problem in health care is the general apathy I see towards self education. I can’t tell you who is on American idol, I have no idea what the latest ipad, ipod, iphone capabilities are but I know how the radiation exposure associated with CT scans. I know it is especially dangerous for young girls. I know the Gardasil vaccine is dangerous. As of September 28, 2010, the Vaccine Adverse Events Reporting System (VAERS) has more than 18,000 Gardasil-related adverse events listed in it, including at least 65 deaths. I guess my point is if people star educating themselves I think a lot of the problems in are system resolve. Obviously emergency management slightly different but as people become more proactive and thoughtful in the management of their care I think progress will be made.

  22. The risk of cancer from a CT scan is not well known. “Quantitative” risks are based on models that assume that radiation damages the DNA of cells and the risk goes up as the amount of damage occurs. This model may not be a true reflection of what actually happens. DNA damage, up to a point can be repaired by cells, so no cancer ensues. The best we can say is that there is likely to be some significant amount of cancer risk from CT scans and their widespread use increases risk – we just do not really know how much.

    Regarding the “MD” comment. There are guidelines for use of CT scans. If the standard of care for doctors were tied to the application of guidelines published by cognizant (unbiased) organizations, then doctors would not be vulnerable to malpractice claims when they do not use a CT scan and they are working according to guidelines. Sadly, the continuing education for doctors is so poor that they are typically unaware of such guidelines or are working to outdated ones. The “fix” is in the hands of the physician community, but they seem to lack the moral imperative to consistently offer their patients safe, efficient and evidence-based healthcare.

  23. How ironic. At present 5 out of 5 plaintiff expert witnesses will testify the CT scan should have been done.

    In the near future 5 out of 5 expert plaintiff witnesses will testify that the CT scan should not have been done.

    Thre are many more negative scans than positive. This is purely defensive medicine at its worst. Someone give us docs in the trenches a better working environment.

    Right now I know no surgeons that will operate for appendicitis without a CT scan saying “cut here”.

    It has becone alleged malpractice to have contrast reaction studying renal stones with IVP, since a CT scan with no contrast dye will never cause a fatal allergic reaction. But now it is 1 in 50,000 immediate deaths (from contrast allergic reaction) or 1 in 250 cancers per scan per lifetime. Once you get cancer you get lots of scans.

    Is someone keeping score?

    Informed consent is an illusion, since the patient has no way to really measure the risk of the action versus the risk of no action.

    We pan scan (head, c-spine, chest, abdomen, pelvis) major trauma victims to the tune of Hiroshima levels of radiation. Funny how a standard of care ignores increased later risk in exchange for immediate reward.