Do X-Rays Cause Cancer?

One study estimates that medical radiation exposure is six times what it once was in 1980, and this is largely due to increased use of diagnostic imaging. In fact, 50% of an individual’s exposure to radiation now comes from medical imaging, in comparison to just 15% in 1980. In part this is because medical innovation has allowed for the use of more informative forms of imaging, such as CT and PET scans, which expose the body to higher concentrations of radiation. The review found that while there aren’t enough studies exploring the effects of medical radiation on cancer risk, there still does seem to be some evidence that medical imaging is linked to an increased risk of developing the disease. For example, patients with tuberculosis who underwent radiation imaging on their chest had increased rates of lung cancer.

How exactly can radiation lead to cancer? Radiation increases an individuals risk of cancer by causing mutations and changes in the DNA of cells. If the changes are in genes that are responsible for cell division, then the cell can eventually become cancerous, but this typically takes 5 – 15 years of consistent exposure to radiation. In addition, children are much more sensitive to radiation than adults, so parents should be particularly cautious and consult with their physician if their child requires consistent medical imaging.

Overall, the increased risk of cancer from medical imaging is likely very small. Nonetheless, to ensure that medical imaging is not increasing your own risk of developing cancer, Dana Farber Cancer Institute recommends you:

1. Keep a history of your radiation exposure from medical imaging, including X-rays, CT scans, and PET scans.
2. If you are required to receive regular diagnostic imaging for a chronic condition, discuss with your doctor if its possible to use imaging with lower doses of radiation or to decrease the frequency of your imaging.
3. Discuss with your doctor for alternatives if your child requires radiation-producing imaging.

Aside from medical imaging, individuals can also be exposed to radiation through treatment. Radiation therapy is a form of treatment for solid cancer tumors in which oncologists blast the tumor site with high doses of radiation. The therapy is part of an unfortunate paradox in cancer care: some therapies used to treat cancer can also cause cancer. Through radiation therapy, the DNA in cancer cells of the tumor is damaged to the point that cells die and the tumor shrinks, but the treatment may also cause changes in the DNA of surrounding healthy cells, causing them to become cancerous. Fortunately, a recent study estimates that the use of radiation therapy has declined for early stage cancers over the past decade, in part because of better surgical methods and other forms of treatment, such as targeted therapies and immunotherapies.

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