CAT scans linked to cancer

CAT scans linked to cancer

I think that most screenings are a waste of time and money, but there’s a bigger reason why you should think twice before getting a CAT scan: Two recent studies have shown that it can increase your risk of cancer.

According to FDA estimates, 1 in 2,000 adults and 1 in 500 kids will develop a fatal form of cancer from radiation exposure. It’s no wonder –CAT scans douse you with up to 750 times more radiation than one X-ray.

That’s disturbing enough in and of itself, but what’s even worse is that millions of people get this test every year and they don’t even need it. A study in the New England Journal of Medicine showed that a full one-third of the CAT scans done in the States are unnecessary.

The study found that of the patients in the group, 30 percent had three scans, 7 percent had at least five, and a whopping 4 percent had more than nine! If you think that seems a bit excessive, you’re absolutely right. To put it in perspective, the researchers said that the radiation from just two CAT scans was similar to the amount of radiation of Japanese post-atomic-bomb survivors–all of whom have an elevated risk of dying from radiation-related cancer.

With over 60 million CAT scans performed every year, that’s a LOT of unnecessary testing–and, more importantly, a lot of unnecessary deaths.

It’s all in the numbers

Radiation is actually a natural force that you’re exposed to every day of your life from things like the sun, rocks, and our food. And the fact is, your risk of dying from natural causes of cancer is much greater than your risk of dying from radiation-associated cancer.

But the concentrated force of radiation that you get in something like a CAT scan only increases your odds. Stick with me and I’ll try to explain how to assess the risk. Radiation is measured in units called millisieverts (mSv). Something like a chest X-ray delivers .02 mSv and is the equivalent of 2.4 days of natural radiation. All in all, that’s not too bad.

But many people these days are getting doused with much, much more than that. When physicians studied the medical imaging records of 1,243 patients to see how much radiation they had been exposed to in a five-year period, they found that, on average, the patients received 45 millisieverts (mSv) of radiation. Twelve percent of them received over 100 mSv. I’d say a good portion of that radiation is coming from CAT scans.

If you’ll take a look at the chart below, you can easily see that CAT scans pack a radiation punch that far outweighs that of an X-ray. These are the numbers released by the FDA:

FORM OF RADIATION                           mSv                Equivalent # of X-rays                NATURAL RADIATION

1. Chest X-ray                                                   .02                          1                                                                 2.4 days

2. CAT scan of abdomen                              10                           500                                                            3.3 years

3. Whole body scan for men                    15.2                         760                                                            5.1 years

4. Whole body scan for women                21.4                       1,070                                                         7.1 years

Take a look at numbers 3 and 4. Did you notice how much more radiation a woman gets from the exact same test? There’s a good reason for this. The first is that women have denser bodies. And while that extra cushion is what we men love about the fairer sex, it’s not a good thing when it comes to radiation.

Women need more radiation in order to get an accurate visual image, but they’re also more sensitive to it. The technicians can’t get a scan of the heart without exposing the breast tissue, and breast tissue is very sensitive to radiation.

A study published in the Journal of the American Medical Association in 2007 found that 1 in every 143 women who get CAT scans at age 20 will develop cancer, while only 1 in 686 men who get CAT scans at the same age developed the disease.

Be sure to know your options

Most doctors use CAT scans to diagnose heart disease. But to what end? It’s all in the risk-benefit ratio. If it’s a life-threatening situation, CAT scans are the obvious choice. But for someone who has no symptoms at all and wants to get the test “just in case,” it’s just not worth the risk. When it comes right down to it, the exposure to radiation will just be the beginning of your problems.

Let’s say your test is abnormal. What’s next? More tests, of course. So you may have no symptoms at all, but if it looks like you have a blockage, you’ll need to get a nuclear stress test and a coronary angiogram–both delivering EVEN MORE radiation. Next thing you know, your doctor tells you that you need bypass surgery, and you willingly go under the knife because you think it’s going to save your life. Never mind that there’s not an ounce of evidence out there that this is going to prolong your life. Quite the opposite, actually.

All because you got a test you didn’t even need.

Even if you do have risk factors for heart disease, that doesn’t mean you need to get a CAT scan. Remember: You have control over your own medical care. Before you blindly agree to one of these tests, ask your doctor a few questions:

  • Do I absolutely need a CAT scan?
  • Are there tests that could be done instead, such as an ultrasound or an MRI?
  • How can I lower my risk of heart disease?
  • How much radiation would I be getting with this test?

One final word about children and CAT scans.

Children are especially at risk of developing cancer from radiation (1 in 500) because their cells divide more rapidly. The other problem is that most kids get much more radiation than they need. Although the machines can be adjusted to deliver 50 percent less radiation, most technicians don’t bother to make the adjustment (that’s based on a study in the American Journal of Radiation).

So remember: Unless the test is absolutely necessary, skip it. But in the event that it does become necessary, make sure the technician is using pediatric-appropriate settings. You can’t be too careful.