Sunscreen and the skin inside a radiation treatment area

This page is for people having radiation therapy who want to know which sunscreen they can use. It explains what NCI does and does not say, and what to ask your radiation team.

You have probably come here wanting a product recommendation. It is fair to want one, but NCI's patient guidance does not give one.

NCI recommends sunscreen for people having cancer treatment: "Use sunscreen and sun-protective lip balm. Wear a loose-fitting long-sleeved shirt, pants, and a hat with a wide brim when outdoors to prevent sunburn."

What it does not do is name a type, an ingredient, or a brand for skin in the area being treated with radiation. It is best not to fill that gap with a guess. Radiation departments give their own instructions about what may go on treated skin, and those instructions are the ones that apply to you.

Ask your radiation team what you may put on the treatment area. That answer beats anything you read online.

Skin inside a radiation field is not behaving like ordinary skin. NCI describes what happens: radiation therapy "can cause the skin on the part of your body receiving radiation to become dry and peel, itch..., and turn red or darker." It may look sunburned or become swollen, and sores can develop that become painful, wet, and infected.

That is part of the reason for a rule that surprises people. NCI says not to use heating pads, ice packs, or bandages on the treatment area during radiation therapy. Ordinary comfort measures that would be harmless anywhere else are off the table here.

It is easy to lose sight of this. The special rules apply to the treatment area. The skin everywhere else is skin, and it needs the ordinary protection NCI describes for anyone having cancer treatment.

That means sunscreen on exposed skin, sun-protective lip balm, a loose long-sleeved shirt and pants, and a wide-brimmed hat outdoors.

NCI advises keeping the area clean and dry so it does not become infected. NCI also notes that peeling, painful, wet skin happens most often where the skin folds, such as around your ears, breast, or bottom.

A treated area that becomes wet and sore is the reaction NCI describes as painful, wet, and infected. That is something to show your team rather than manage on your own.

Radiation courses run over weeks, and the skin instructions you get at the start are meant to carry you through the whole thing. It is worth being specific.

• May I use sunscreen on the treatment area at all?
• If yes, which type, and is there a gap I should leave before a session?
• What may I use to wash the area?
• Which products should I stop using entirely for now?
• Do these rules change after my last session?

Write down the answers. Several weeks in, when your skin is dry and sore, it is tempting to reach for whatever is in the bathroom cabinet. Having the rules written down helps you stop and check first.

How to care for treated skin after radiation ends is a question for the team who treated it. Ask before your final session, while you still have easy access to them.