Did the Recent NEJM Article Overstate Any Cancer Risk Associated With CT Scans?

An article titled, Computed Tomography-An Increasing Source of Radiation Exposure, published in the Nov. 29 issue of the New England Journal of Medicine (NEJM) has re-ignited a firestorm in the medical community and created confusion in the minds of many of our patients.

The study claimed that up to 2 percent of all cancers in the United States may be caused by radiation received from CT scans and equates radiation exposure and effects experienced by many atomic bomb survivors in Japan to present day patients who receive computed tomography (CT) scans.

The ACR immediately issued a response in order to allay patient fears engendered by media reports on the study, lay out what the radiology community has been doing to address radiation risk, and help give physicians some guidance on what they might say to their patients. The response was referenced in many newspaper articles nationwide and I was interviewed by several newspapers regarding this issue.

But, I wanted to find out what you think about the utilization of CT and any associated cancer risk. Please write in with your thoughts regarding how CT is being utilized and whether you think the cancer risk was overstated in the NEJM article. I look forward to hearing what you have to say.

Comments

[Edwin Rivera]

As a radiologist I hope the ACR is planning a response in major newspapers as to inform the general public about this issue and what we are doing to improve patient safety.

[Arl Van Moore Jr., M.D.]

The ACR sent the response to the NEJM article (posted to the front page of the ACR Web site) to all the major newspapers, the trade media, and to the network TV news programs.

Excerpts from the response and from interviews that I did were carried in major newspapers nationwide (including the Wall Street Journal and others) and elsewhere.

Arl Van Moore Jr., M.D.

[Mark Guenin, M.D.]

Within the realm of radiology, there's a temptation to pat ourselves on the back and say, "Wow, what a marvelous job we're doing alerting others to the potential danger of our own tools. How noble of us."

However, we need to realize that our efforts are not universally applauded. Go ahead and read other medical blogs from those outside radiology, and you'll realize there's a bit of a backlash against articles like these.

Below is a link to a post on "White Coat Rants." http://whitecoatrants.wordpress.com/2007/11/30/if-the-disease-doesnt-kill-ya-the-ct-scans-will/.

Please don't complain to me about the content -- I didn't write it. But realize these opinions are out there, they are getting expressed, and they are finding a sympathetic audience:

I urge you to read the whole post.

Mark Guenin, MD

[Drew Lambert, M.D.]

I was interviewed by one of the local newspapers the day this article came out. The ACR response was useful to me in preparing for the interview. The subsequent news article was accurate and included most of the recommendations to patients listed on the ACR site.

Drew Lambert, M.D.
Charlottesville, VA

[Ryan Arnold, MD]

I am a 3rd-year radiology resident going into Pediatric Radiology.

Having recently studied for and passed my physics boards, including the radiation biology section, I find it credible that a chest CT, imparting the same radiation dose as 100 chest xrays or 3 years of natural background radiation, would increase a patient's lifetime risk of breast and lung cancer.

http://www.cancer.gov/cancertopics/causes/radiation-risks-pediatric-CT

The science behind the NEJM article has been meticulously detailed in the BEIR VII phase 2 report. I don't understand why we are so quick to deny or play down this data. Although not perfect, this document represents the most comprehensive information we have about the effects of low-dose radiation.

Dr. Fred Mettler, for one, is a believer in the radiation risk:

http://news.yahoo.com/s/usnews/thedoctorsaysgetactscanshouldyou

Because radiation-induced cancers are not distinguishable from other cancers, and because it takes 5-20 years for cancer induction and discovery, a study linking CT scans to radiation-induced cancer would be very challenging to conduct prospectively. I sincerely hope such a study is forthcoming.

The scariest sentence in the whole NEJM article is: "53% of radiologists and 91% of emergency-room physicians did not believe that CT scans increased the lifetime risk of cancer."

This ignorance constitutes a grievous failure on our part as radiologists to educate ourselves and our clinical colleagues.

[Wayne Davis, MD]

Working in a community hospital based group I see incredible over-utilization and over-exposure of children and young women out of the ED (despite my efforts to try and curb this practice).

The NEJM article and associated news reports about the article stimulated one women to ask one of our technologists today whether her CT (fourth one for the same problem in 2 months) was really necessary which is really a step in the right direction. Sometimes it takes dramatic, maybe overstated news to bring otherwise unknowing people to action.

[James Rademacher, MD]

2% may be high but if accurate then cardiac nuclear is probably 1%. Another area of over utilization and moving toward younger and younger female patients.

When this issue hit the press earlier this year the ACR indicated it was going to work with urology organizations on how and when to image stone formers. Some of these young people are getting multiple CT scans each year.

The ACR was also going to work with med schools and residency accreditation to get education around radiation into these programs and included in certification exams. Where are these initiatives going? The ER is a problem. So very many (minimal) trauma patients get CT'd head to pubis and so many of them are negative.

[Ronald E. Cordell, M.D.]

Hopefully the ACR will use this as a "teachable moment" and as a rallying point for radiologists. We all see patients, especially through the ER, who have had multiple abdominal CT scans for "abdominal pain to rule out stones" in a 1-2 year period.

Obviously this is inappropriate when there are no stones present at all on any of these multiple scans. The radiology community needs to acknowledge that some patients are being subjected to inappropriate and sometimes excessive imaging. We state that we are the physicians best trained to perform imaging and this is true. However somewhere along the way we have forfeited our role as consultants in what studies are appropriate.

I know we have the appropriateness criteria, but how many ER docs know about them or use them? Maybe we should start reclaiming our role as the best all-round imaging consultants, from what exams are ordered to our final interpretation.

The question then arises, "where do we find the time? We are all running just to stay in place." Well, maybe we could start by having ACR representatives sit down with American College of Emergency Medicine representatives and come up with agreed upon "best practices for commonly seen ER patient problems" that would then be disseminated to the ER physicians as a collaboration between us and most importantly, their own organization.

Maybe the idea of a "radiation cumulative dose card" for patients should be looked into and discussed further to determine whether it is a good or bad idea. Maybe this is an opportunity for us to ramp up our "branding" of radiology as the best trained in these aspects of patient care. While I agree that we should make sure that the public is not alarmed unnecessarily, we should begin the long-term retrospective and prospective studies to determine what the effects of medical radiation exposure are and that we really are providing studies that are as safe as possible.

We will all feel better having factual information. This also meshes with our concern over the issue of self-referral and economic referral. I think we should look at this as an opportunity instead of just focusing on it as a threat. We can do the work to show the physician community and the public that we take our role as imaging specialists seriously.

Ronald E. Cordell, M.D.

[Alfonso Gay, Jr., M.D.]

I get a sense of mixed messages from our leadership regarding this issue. The ACR leans more toward this is an overstated problem while RSNA says the report is accurate. On the one hand we as radiologists like the report since it reminds everyone CT is not a toy that anyone can play with (i.e. in office CT scanners for non-radiologists). On the other we make a living interpreting CT so we don't want to scare anyone away from having one. The hard but correct answer lies in proper utilization of the technology. First of all overutilization of CT in the office setting by non-radiologists should be regulated. What is happening in Maryland is a good example. Secondly, we need to have the courage to address the overutilization we see in the ED. How many CT kidney stone protocols really need to be performed? How many positive PE studies do we actually see? How about the r/o PE study in patients with IVC filters in place? Admittedly this will be a tough road as ED physicians are truly addicted to CT imaging not only because of its diagnostic strength but for medicolegal reasons. It is no surprise that the American College of Emergency Physicians was one of the first to trash the NEJM report.

[Shailendra Chopra, MD]

As a radiologist who has gone from academic to community practice, there is no doubt that there is over utilization of CT. There is also no doubt that a lot of it is due to defensive practice of medicine as outlined in the article. The defensive medicine is a direct function of the malpractice liability environment. If tomorrow the government put a moratorium on all health care related lawsuits, that practice would come down to negligible within a year. However, that is not going to happen.

In that case it behooves us as radiologists to reduce the radiation dose from CT as much as reasonably achievable (Remember ALARA). How to do it? If you are in community practice, one of the easiest ways is to modernize your protocols. If you are in doubt ask your nearest university radiology department for help. Here are a few specifics.

1. Are all your scans carried out with and without contrast irrespective of the indications? I have noticed this to be true particularly for CT abdomen at many community hospitals. For general abdominal symptoms, CT abdomen and pelvis with contrast in the portal venous phase (75-110 seconds depending on the number of detectors) will suffice very well. An additional run without contrast has NOTHING to contribute. If you don’t agree with this go and relook at the last 100, 1,000, 10,000 cases and determine where you saw findings on non contrast CT that you could not see on contrast enhanced run.
2. Do you routinely perform a three phase CT in all abdomens irrespective of the indication? Remember, other than for known or highly suspicious cases of cirrhosis, liver, pancreatic or renal masses, three phase CT has NOTHING to contribute. Even in the exceptions mentioned above you are better off developing your MR protocols to sort out those problems. It will give more diagnostic information in addition to the information that you would get from a three phase CT.

3. Do you routinely perform additional delayed images through the kidneys and pelvis? It has nothing to contribute unless the patient has hematuria under investigation. Chances are if you are doing this routinely, you are performing your first phase in the arterial phase and totally missing the most optimum portal venous phase.

Just these steps alone will reduce your radiation dose from CT by half to two thirds. Changing practice is always difficult but is easy if you understand the rationale.
I’d be happy to share my protocols with whoever wants them.