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Side effects of radiotherapy

Find out about the side effects of external radiotherapy for cancer of the back passage (rectal cancer) and how to cope with them.

Side effects tend to start a few days after the radiotherapy begins. They gradually get worse during the treatment. They can continue to get worse after your treatment ends. But they usually begin to improve after 1 or 2 weeks.

Everyone is different and the side effects vary from person to person. You may not have all of the effects mentioned.

Side effects can include:

Long term side effects

Most side effects gradually go away in the weeks or months after treatment. But some side effects can continue or might start some months or years later.  

Side effects if you have chemotherapy with radiotherapy

Chemotherapy combined with radiotherapy can make some side effects worse. Combining these treatments is called chemoradiotherapy.

Last reviewed: 
17 Sep 2015
  • Metastatic Colorectal Cancer: ESMO Clinical Practice Guidelines

    Van Cutsem (and others)
    Annals of Oncology, 2014. Vol 25, Issue 3

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