Acute side effects are those that happen during and within a few weeks after treatment. They are usually more temporary and tend to resolve, although this is not always the case. Sometimes severe acute side effects can result in late effects.

Late side effects are side effects that can occur 3 months after completing radiotherapy. Late side effects are less common. They may not show themselves during or immediately after radiation therapy but occur later on. The risk with late side effects is that they could be permanent or irreversible and become a more long term situation.

Acute side effects

  • Nausea and vomiting – sometimes patient need to be admitted for hydration intravenously
  • Diarrhoea due to irritation of the small and large bowel
  • Fatigue
  • Loss of appetite with loss of weight is common
  • Indigestion
  • Skin reaction
  • Rarely – irritation of the food pipe or stomach that can cause bleeding
  • Some patients cannot get enough nutrition while the above side effects occur and occasionally need a feeding tube either via the nose (naso-gastric tube) or stomach (gastrostomy tube) to support them while they are having treatment.

Late side effects

  • Inadequate function of the pancreas causing high sugar levels and diabetes
  • Inadequate function of the pancreas causing loose bowel motions and inadequate digestion of food
  • Inflammation of the liver or deterioration in thethe function of the liver
  • Deterioration in the function of the kidney – this is uncommon
  • Narrowing or ulceration (can cause bleeding) of the stomach, small or large bowel
  • Very rare – another tumour in years to come as a result of the radiation therapy.
  • Some side effects around changes in bowel habits and blood sugar levels, may need longer term management as treating the pancreas can make these problems more obvious and long term. This is uncommon but will be monitored for.

It is important to report these symptoms to the doctor looking after you as some of these symptoms can be managed.

What can help reduce side effects?

Resting as needed can help with fatigue in some patients. For bowel symptoms such as diarrhoea, it is important to keep hydrated, the doctor may prescribe medication to reduce this. Similarly with nausea and vomiting, and cramping, the doctor will advise you about which medication is suitable for you. These side effects are rarely severe with modern targeted radiation therapy and commonly settle quickly after treatment.

Information and Guidance

Radiotherapy Treatment Process

Click below for a video that shows the external beam radiotherapy treatment process.