Radiotherapy emits high-frequency waves to a specific target (the cancer cells). The targeted cells are in turn killed. However as the waves have to pass through skin, at the point of entry, and the point of exit, skin is often affected. This is because radiotherapy targets all cells, it is not selective, so any cells, including skin cells, can be injured. Describing how radiotherapy affects the skin can be compared to the sunlight and becoming sunburnt. Depending on the different colour of skin, and the location of the skin, too much sunlight can lead to you becoming burnt. And sunburn can also vary; some people experience mild sunburn that goes away or is easily managed with creams, while some people experiencing extreme sunburn that damages the skin. People also forget that unlike the sun, radiotherapy isn’t absorbed, so as well as having an entry site, the rays also exit the body via the skin. Therefore if you are having radiotherapy to your breast, for example, you may find the skin on your shoulder and back become red and irritated if not managed.
Radiotherapy causes the skin to become very dry and delicate. It is important to use creams and lotions that won’t further exacerbate the skin's condition. Products that contain perfumes or metals tend to be drying, and therefore should be avoided. Natural and organic ingredient-containing products are usually more soothing and calming than chemical containing products. It is also good to note that unless you are having chemotherapy at the same time, the skin that isn’t in the range of radiotherapy should not be affected by radiotherapy. Radiotherapy can make you feel nauseous, so you may find your skin becomes dry due to decreased nutritional or fluid intake.
Mild, gentle exercise is usually recommended for those undergoing radiotherapy treatment. And swimming, on the basis of it, is a low impact gentle form of exercise. However, you may find that your treating doctor advises you not to swim while undergoing radiotherapy treatment. This is because chlorine and seawater are very drying for the skin. Also, it can cause infections if you have broken skin while swimming. If it is important to continue swimming during treatment, speak to your doctor regarding expectations versus reality.
Skin problems caused by radiotherapy should resolve once you finish treatment. But not necessarily immediately. Sometimes you may find that your skin actually gets worse before improving.
If you do find though, there are no signs of improvement for a couple of weeks, or that your skin is becoming worse, it is important to tell your doctor or nurse.