Side Effects

Colorectal cancer

Side effects during / soon after treatment (Early or “acute” side effects) General

Early side effects

  • Fatigue
  • Nausea (Uncommon)
  • Rectal discomfort
  • Bowel & bladder urgency and frequency (i.e. may need to pass stools or urine more often, and without as much warning)
  • Burning when you need to pass urine

What can help reduce acute side effects?

There are many ways to minimise the side effects during treatment. It is important that you let the treating team know about any side effects you are experiencing. Your doctors may advise supportive measures or prescribe medications to relieve some of these symptoms. The team is here to support you throughout your treatment.

Late or long-term side effects

Most people tolerate treatment well for many years after treatment. There are some uncommon side effects that can happen in the long-term. You should speak to your doctor if these uncommon side effects occur. Pelvic radiation can affect fertility depending on your situation – please discuss this with your oncologist. For women radiation can sometimes cause narrowing and dryness of the vagina.

Small bowel – bleeding, stricture (narrowing of the intestine), perforation (a hole in the wall of the bowel), malabsorption (poor absorption of nutrients) (Very uncommon)

Rectal damage – reduced capacity, urgency, frequency, bleeding, incontinence, fistula formation (an abnormal opening in the bowel) (Very uncommon)

The skin or internal tissue may become less stretchy and harden (fibrosis)

What can be done to treat late side effects?

You should speak to your doctor if these uncommon side effects occur. Depending on the side effect, your doctor may refer you to a specialist or surgeon to manage these.

Other side effects