Radiotherapy for testicular cancer can cause some side effects, but they are usually mild and go away after treatment. Common side effects include:

Skin reactions
Radiotherapy can make your skin feel sore or irritated in the treated area. This usually happens about 2-3 weeks after treatment. This is completely normal and should get better over time. Your healthcare team may suggest vitamin E supplements or soothing creams to help your skin heal. It’s also best to keep the area covered and protect it from the sun. You might notice your skin gets a little darker, but this will fade.
Feeling tired
You may have less energy than usual. A combination of treatment and travel might make you feel tired. Taking short naps or mild sleep medication could help you rest better.
Feeling sick
Some people feel sick or have an upset stomach. Your doctor can prescribe medicine to help with nausea.
Diarrhoea
If you're having stomach trouble, cutting back on high-fibre foods like fruits, vegetables, and wholewheat products might help. Drinking plenty of fluids can also keep you from getting dehydrated.