Sun Exposure After Radiation

Last Modified: May 12, 2006


Dear OncoLink "Ask The Experts,"

I had 35 radiation treatments about five years ago and was told not to go out in the sun. After this length of time, is it OK to be in the sun if I apply sunscreen with a SPF 15 or above?


Neha Vapiwala , MD, Senior Editor of OncoLink from the Department of Radiation Oncology at the Hospital of the University of Pennsylvania, responds:

Radiation therapy is the use of ionizing radiation (x-rays) to treat cancer cells. Ultraviolet rays from the sun are also considered ionizing radiation. Excessive exposure to ionizing radiation CAN potentially cause changes (also known as "mutations") to the DNA of your body's cells. These mutations can lead to abnormal and uncontrolled cell growth, which is called cancer.

Both radiation therapy and the sun's rays can lead to skin damage and irritation. As you probably know, excessive sun exposure is the main cause of most skin cancers. Thus, as a general rule, you should always use sun protection when you are outdoors, including sunscreen of SPF 15 or greater.

Although you did not indicate the specific location of your body that was treated with radiation (i.e. the treatment site), it should be fine to have sun exposure as long as you use good sun protection (sunscreen, hat, sunglasses). The area that was treated can be sensitive to sun exposure, but not necessarily more than any other part of the body.


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