I also heard sun protection is lifelong after radiation treatment, due to changes in skin, and radiation ionization, which increases skin sensitivity, risk of cancer. I was specifically told to avoid direct sun exposure in radiated field for a year with proton therapy, for other radiation treatments, general head and neck sun protection precautions. If in the sun longer than 10 minutes, sunscreen with at least SPF 45 should be used, along with wearing protective clothing, collar, brimmed hat. With Erbitux, you're told to avoid the sun also, and for two months after treatment ceases due to sensitivity of the skin, and reducing its effectiveness. I have non cancer medications that increases sun sensitivity, effectiveness with sun exposure, so there are warning labels on them or in the drug insert.