Too much medical care is not always better – or healthy. Computed tomography (CT) is one such example. CT scans are used to diagnose many health complaints. The number performed each year has increased by nearly one-third (30%) since 2007. I wrote about my wife getting a (largely unnecessary) CT scan 12 years ago. As far as we know the biggest risk was avoided when she almost got it at a hospital rather than a free-standing imaging center. Prior authorization saved her $2,300. I paid out-of-pocket for a full body CT scan 10 years ago for $1,200. It found nothing but I’m not convinced the radiologist took it seriously since she wasn’t told to look for anything specific. It was little more than a service sold to the worried well. One problem with the overuse of CT scans (and MRIs) is false positives. Your doctor may find something ambiguous – but benign – that requires further investigation. What would have gone away a month later resulted in an expensive CT scan, a biopsy, a pathology report along with numerous doctor visits. Doctors generally recommend forgoing unnecessary CT scans in asymptomatic patients.
There may be other reasons to avoid CT scans of dubious merit. A new theoretical analysis claims CT scans may cause up to 103,000 cancers each year. The following is from Science Alert:
More Americans are receiving computed tomography (CT) scans than ever before, and while this technology can save lives, some scientists are concerned that low doses of ionizing radiation could increase cancer risk.
Importantly, at an individual level, the theoretical risk of developing cancer from a CT scan is thought to be very low, if it exists at all. Patients should not hesitate to undergo these tests if they are considered medically necessary.
In a study published in April, a team in the US and the UK predicted that low levels of ionizing radiation from CT scans could theoretically account for 5 percent of all new cancer diagnoses in the US. CT scans conducted in 2023 could be responsible for an estimated 103,000 future cases of cancer.
Supposedly, CT scans increase cancer risk factors, as much as alcohol consumption. The estimates are based on high radiation events like Hiroshima.
The potential association is mostly based on long-term studies of atomic bomb survivors and those exposed to nuclear power plant meltdowns. For instance, in a group of 25,000 Hiroshima survivors, who received a dose of ionizing radiation on par with three or more CT scans, there was a slight but significant increase in cancer risk across a lifetime.
As of now, these are just theoretical risks, but that doesn’t mean they aren’t worth considering. While scientists know that high doses of radiation cause cancer, conclusive evidence to link low-level radiation to cancer is lacking.
On the other hand, CT scans are also associated with improved health outcomes.
“Any risk from a CT scan of a sick patient is likely much less than the risk of the underlying disease,” said Cynthia McCollough, CT imaging expert and past president of the American Association of Physicists in Medicine.
In a large national trial, for instance, there was a 20 percent decrease in lung cancer deaths among smokers and ex-smokers who received low-dose CT scans compared to those who only had a chest X-ray.
Experts also suggest some people may be more susceptible to the ill effects of low-dose radiation than others, with the dangers more severe in young adults and children. That makes sense: a 65-year old on Medicare probably only has 20 to 30 years in which to develop cancer, while a 15-year old has 70 to 80 years.
The study was published in JAMA Internal Medicine.
Read more at Science Alert: CT Scans Projected to Result in 100,000 New Cancers Across The US