Long term side effects of radiotherapy

Depending on the area of the body you have treated, you might have any of these long term side effects after radiotherapy:

  • your skin might look darker than it was before in the treated area – as if it is suntanned
  • your skin in the treatment area will always be slightly more sensitive to the sun
  • your skin might feel different to touch
  • your hair might grow back a different colour or texture in the treatment area
  • you might have permanent hair loss within the treated area
  • you might develop red spidery marks on your skin (telangiectasia) caused by small broken blood vessels
  • drainage channels to the arms or legs can become partly blocked resulting in swelling called lymphoedema
  • you might be unable to become pregnant or father a child if your ovaries or testicles were in the radiotherapy field
It is important to remember that radiotherapy only affects the area of the body being treated. Changes to a part of the body outside the treatment area won't have been caused by the radiotherapy.

Long term effects on tissue

Radiotherapy makes tissues less stretchy. Doctors call this radiation fibrosis. How this affects you will vary depending on which part of your body was treated. Fibrosis may cause any of the following:

  • your bladder could become less stretchy and hold less urine after treatment to your abdomen, so you need to pass urine more often
  • your bowel habit may change after treatment to your pelvis
  • your breast might be a slightly different shape, feel firmer or harder after breast radiotherapy
  • your vagina could become narrower and less stretchy after treatment to your pelvic area
  • your arm may swell after treatment to your shoulder
  • your leg may swell after treatment to your groin
  • you may have an increase in breathlessness due to your lungs being less stretchy, after treatment to the lungs or chest
  • narrowing of the food pipe (oesophagus) making it difficult to swallow, after treatment to your neck or chest

Long term effects on the pelvis

The pelvis is the area between your hips. Radiotherapy to the pelvic area might cause:

  • changes to your bowel habit
  • bladder inflammation causing pain in your tummy (abdomen) and feeling like you need to pass urine more often (let your doctor know if this happens as it could be an infection)
  • fine cracks in the pelvic bones
  • your digestive system to stop taking in (absorbing) vitamin B12 from the food you eat - this can cause a vitamin B12 deficiency
  • bleeding from the bladder, bowel or vagina - always let your doctor know if this happens
  • tingling, weakness or loss of sensation in one or both legs – this is very rare and is called radiotherapy induced lumbosacral plexopathy (RILP)
  • weaker pelvic bones - you might have a DEXA scan to check them

These changes can gradually appear over a long time, sometimes several years. Talk to your doctor if you had radiotherapy in the past and are worried about side effects.

Newer ways of giving radiotherapy

Radiotherapy is more accurate than it has ever been. Current radiotherapy techniques, such as conformal radiotherapy and intensity modulated radiotherapy (IMRT), accurately shape the radiotherapy beams to fit the cancer. This means less healthy tissue receives radiation, and so there are fewer side effects.

Research continues to look into ways to make radiotherapy even more precise.