How many people have to die before you’ll pay attention? Like many of you, I read the article but it didn’t really stick. Rather, I filed it in the “interesting tidbits” folder on my brain’s hard drive. Somehow 29,000 people with cancer just didn’t register as a big number.
Until I thought I could be one of them.
The Number
I was harried, running late for a meeting, questioning my decision to try to shoehorn a PCP appointment into my lunch break. Then again, this was a routine follow-up of some labs and I, of course, am the picture of health. Well, I am if you exclude my LDL. It turns out that on a check 12 months earlier, my LDL was found to be running a few heart attacks higher than normal. I took this as a sign, combined with my ballooning waist, middle-ish age, and nagging wife, that I needed to do something.
A CT scan of the chest axial section showing lung cancer. According to a recent Archives of Internal Medicine paper, radiation from CT scans are responsible for 1.5% to 2% of all cancers in U.S. patients.
Still, I wasn’t ready for “something” to include an anticholesterol medication. Instead, I chose the masochistic route and hit the treadmill. And the bike. And a little less of the dinner plate. As a result, I had lost 30 pounds, a handful of pant sizes and, while I wasn’t exactly “in shape,” I did find myself shaped a little less like the Michelin Man.
Triumphantly, I was returning to vanquish my tormentor—the PCP who foolhardily recommended I start a medication.
Sitting in the office awaiting the news of my post-weight-loss cholesterol, my grin was wide and smug—and apparently still overflowing with LDL. I was devastated. 259? I lose weight and my LDL actually goes up!?! I could feel the foam cells in my coronary plaques twitch with delight as they mockingly gorged on chylomicrons.
Undeterred, I inquired what my options were, secretly hoping the answer would be more red wine. Emboldened by my supersaturated serum, my PCP declared it was time for a statin. Alternatively, he noted that I could get a CT angiogram of my coronaries and, if they were clean, I potentially could bypass drug therapy. Thoughts of avoided myalgias happily flittered across my mind until they stumbled onto the number 29,000. It was then that I recalled the recent Archives of Internal Medicine paper.1
The Study
Using risk models based on the known biological effects of radiation, researchers estimated that approximately 29,000 people would develop cancer from the radiation associated with CT scans in 2007 alone. To arrive at this number, the authors used data showing that 1.5% to 2% of all U.S. cancers could be traced to the radiation from CT scans.
Not surprisingly, the most commonly utilized CT scans—namely, abdominal (14,000 a year), chest (4,100 a year), and head (4,000 a year)—accounted for the most morbidity. However, CT angiography, with its super-high dose of radiation, was projected to contribute 2,700 cancers a year. Apparently, my PCP didn’t read this article.
In terms of types of malignancy, lung cancer leads the list with 6,200 projected CT-induced cancers per year, followed by colon cancer (3,500 a year) and leukemia (2,800 a year).
The Names
If the numbers from this study hold, then about 1 in every 2,000 CT scans results in a new cancer. That would mean that I’ve dished out several cancers during my practice. In fact, I’ve ordered many thousand CT scans over my career—give or take a cancer. So my pen has, statistically, caused approximately three cancers.