Radiotherapy effects on your blood

Radiotherapy sometimes slows down the cells in the bone marrow that make your blood cells. 

This is more likely if you're having treatment to a large area of your body. Or having treatment to your:

  • leg bones

  • chest

  • tummy (abdomen)

  • pelvis

Having chemotherapy with radiotherapy can make the effects on the bone marrow worse. You have blood tests before your chemotherapy to check your blood count. 

Effects of low blood cell levels

Tiredness and feeling short of breath

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

Higher risk of infection

You could be more at risk of getting infections if your white blood cell count falls very low. This is called neutropenia. You might need a short rest from treatment so that your blood count can go back to normal.

Chemotherapy can also affect the number of white blood cells. So having chemotherapy and radiotherapy together can make this worse.

Total body irradiation (TBI)

You have total body irradiation (TBI) before a stem cell or bone marrow transplant.

TBI can affect your red and white blood cells. It can also affect your platelet count. Platelets clot the blood and if they are low you might be at risk of bruising and bleeding. 

Because of this, you have regular blood tests during your treatment to check that you have enough red and white blood cells and platelets. 

Worries about treatment side effects

You may feel anxious about radiotherapy side effects and this is normal. It can help to talk through any worries you have with your doctor, nurse or radiographer.

  • Basics of Planning and Management of Patients During Radiation Therapy 
    A Mukherji
    Springer, 2018

  • External Beam Therapy (Radiotherapy in Practice) Third Edition
    Peter Hoskin
    Oxford University Press, 2019

  • Hematological Changes Following Low Dose Radiation Therapy and Comparison to Current Standard of Care Cancer Treatments
    A Jameus and others
    Dose response, 2021

Last reviewed: 
18 Mar 2024
Next review due: 
18 Nov 2027

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