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Radiotherapy effects on your blood

Radiotherapy treatment can affect your bone marrow and blood cells. 

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
  • chest
  • tummy (abdomen)
  • pelvis

Effects of low blood cell levels

You feel tired and breathless if your level of red blood cells is low (anaemia). You might need a blood transfusion to boost your red blood cell count. Your doctor may suggest that you have hormone injections (erythropoietin injections)  that encourages the body to make red blood cells.

You could be more at risk of getting infections if your white blood cell count falls very low (which is rare). This is called neutropenia. 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.

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

Last reviewed: 
14 Mar 2016
  • De Vita, Hellman, and Rosenberg's Cancer: Principles and Practice of Oncology (9th edition)
    De Vita, V.T., Lawrence, T.S. and Rosenberg S.A.
    Lippincott, Williams and Wilkins, 2011

  • External Beam Therapy
    Peter Hoskin
    OUP Oxford, 30 Aug 2012

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