Where did your friend get that information? As far as I know, that is not true. If you are out in the sun, I would definitely not expose the radiated skin to the sun to avoid irritating the area more.
Long exposure in the sun is not good for anyone even if you don't have cancer.
Just cover yourself appropriately.
When in doubt, ALWAYS ask you Radiation Oncologist about what you can and can't do.
yes because you can get a different kind of cancer....brittany