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Posted by on Mar 12, 2010 in Health care

In Defense of (Some) High-Tech Screening Tests in POTOS

In Defense of (Some) High-Tech Screening Tests in POTOS

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Thanks to a new editorial at the Archives of Internal Medicine web site, much is being made of the high-end technology that was used to recently examine POTOS’s health status. At issue, according to cardiologist Rita Redberg, the journal’s editor, is the ill-advised use of 2 noninvasive screening testselectron-beam CT (EBCT) to look for coronary calcium (a marker of coronary heart disease) and virtual colonoscopy to look for colon cancer. Redberg argued that both tests unnecessarily exposed POTOS to radiation, which increases his risk of cancer. Moreover, she maintained, their use in the President stands as a hallmark of what’s wrong with the US’s expensive test-heavy health care.

With respect to the criticism of screening EBCT, Redberg cited Kim et al, who estimated that the lifetime radiation-induced incidence of cancer from a single EBCT scan in a 55-year-old man is 8 per 100,000 persons. (Most of the increased cancer risk is due to an increased risk of lung cancer [6 per 100,000 persons].)* Redberg further argued that the radiation-induced cancer risk of EBCT does not outweigh the benefit of this test in low-risk persons, like POTOS. To support this contention, she cited the 2004 recommendation of the US Preventive Services Task Force, which advised against screening for coronary heart disease with resting ECG, an exercise treadmill test, or EBCT in low-risk persons.

What isn’t crystal clear, however, from the USPSTF recommendation is what constitutes a low-risk person. It is generally assumed to be someone with a less-than-10% risk of MI during the next 10 years. However, it is worthy to consider whether a less-than-10% MI risk should be parsed further when the patient in question is POTOS.

Obama’s risky smoking habit, the depth of which is unclear, is otherwise well known. Assuming that the President is not taking antihypertensive medication, his 10-year risk of heart attack is 7%, according to the online formula provided by the National Cholesterol Education Program. If Obama didn’t smoke, his 10-year MI risk would be 3% (Plugged-in values for the online formula were taken from an AP report on President Obama’s health status.)

Now: Is a 10-year MI risk of 7% low, if we’re talking about the President, and Joe Biden’s next in line? And Nancy Pelosi after that? While nobody’s maintaining that Obama’s smoking habit should take a back seat in relevance to his coronary calcium score (via EBCT), the latter information is debatably important in someone whose health affects many, many (did I stress many?) people. 

The issue is not that Obama deserves superior health care, which screening EBCT evidently doesn’t provide (at least on a population level, circa 2004), because he is the President; the issue is that extra measures can arguably be taken to obtain more information specifically on Obama’s cardiac health, given that he is a smoker and POTOS. 

Redberg also implicitly chastised POTOS’s physician for ordering a virtual colonoscopy to screen for colon cancer, “even though this screening is not recommended in [Obama’s] age group.” Redberg again cited the USPSTF, which recommended screening for colon cancer at the age of 50 years (Obama is 48) with fecal occult blood testing, sigmoidoscopy, or colonoscopy. (You talk to most physicians, and they’ll generally recommend screening colonoscopy, beginning at the age of 50 years.)

Redberg noted that the USPSTF does not recommend virtual colonoscopy for screening purposes, because of 1) a lack of supportive evidence to justify its use (again, on a population level, this time circa 2008) and 2) the unnecessary exposure to potentially cancer-inducing radiation (like with EBCT).

However, in an AP article from today, the White House countermanded Redberg by stating that earlier screening for colon cancer is sometimes recommended in high-risk groups like African Americans.** Further, the advantage of virtual colonoscopy over conventional colonoscopy is that the former doesn’t require sedation, which might necessitate a transfer of Presidential power to [shudder] Joe Biden.

N.B.–It is assumed that virtual colonoscopy was performed on the President by means of CT, rather than MR. Unfortunately virtual colonoscopy, like conventional colonoscopy, requires colon preparation (and for anybody who’s undergone a colonoscopy, the 24-hour prep is the decidedly unpleasant part).

* Kim et al also noted that the radiation exposure during EBCT varies widely.

** POTOS is black.

Reconstructed CT images of a colon (not Obama’s) from the National Cancer Institute.

bmartin (1127 Posts)

A native East Tennessean, Barbara Martin is a formerly practicing, board-certified neurologist who received her BS (psychology, summa cum laude) and MD from Duke University before completing her postgraduate training (internship, residency, fellowship) at the Hospital of the University of Pennsylvania in Philadelphia. She has worked in academia, private practice, medical publishing, drug market research, and continuing medical education (CME). For the last 3 years, she has worked in a freelance capacity as a medical writer, analyst, and consultant. Follow Dr. Barbara Martin on and Twitter.