Radiotherapy effects on your blood | Cancer Research UK
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Radiotherapy effects on your blood

Nurse and patients talking about cancer

This page tells you about how radiotherapy can affect your bone marrow and blood cells. There is information about


How radiotherapy affects your blood

Radiotherapy sometimes slows down the cells in the bone marrow that produce your blood cells. This is more likely if you are having a large area of the body treated or with treatment to 

  • The bones of your legs
  • Your chest
  • Your tummy (abdomen)
  • Your pelvis

Effects of low blood cell levels

If your level of red blood cells is low (anaemia), you feel tired and breathless. You might need a blood transfusion to boost your red blood cell count. If you can't have blood transfusions your doctor may suggest that you have erythropoietin injections. Erythropoietin is a hormone that encourages the body to make red blood cells.

If your white blood cell count falls very low (which is rare) it is called neutropenia. You may be more at risk of getting infections. You might need a short rest from treatment so that your blood count can go back to normal.

People having total body irradiation (TBI) before a bone marrow transplant or stem cell transplant have low levels of red cells as well as white cells and platelets. Platelets are cells that help the blood to clot and if they are low you may be more at risk of bruising or bleeding.

If your bone marrow is likely to be affected, you have regular blood tests during your treatment to check the number of red blood cells in your blood.


More information about radiotherapy

Find out about

Other radiotherapy side effects

External beam radiotherapy

Internal radiotherapy

Total Body Irradiation (TBI)


Erythropoietin (EPO) injections

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Updated: 14 March 2016