Bowel (Colon) Cancer


Colon cancer starts in the colon and can affect anyone, especially as they get older. 

Colon cancer is one of the most common types of cancer, affecting millions of people each year.

Colon cancer is a type of bowel cancer. Other bowel cancers are rectal cancer and anal cancer. These are named after places they start. Sometimes colon and rectal cancer are grouped together and called ‘colorectal cancer’.

The bowel is a very long organ and tumours cause different problems depending on if they are at the start, middle, or end of the bowel. They also require different treatments.

Colon cancer can spread to other parts of the body, such as the liver, brain, lungs and lymph nodes. When this happens, these secondary tumours are called metastases.

Radiation Therapy and Colon Cancer

The best person to talk to about radiation therapy for colon is a radiation oncologist. A radiation oncologist is a specialist doctor who is part of the team that takes care of people having radiation therapy.

You can ask your doctor for a referral to a radiation oncologist to learn if radiation therapy is an option for you.

The Treatment Team

Doctors make a treatment plan for each person based on:

  • the type of cancer
  • where the cancer is
  • other treatments tried
  • the person’s health.

The type of treatment a person gets is worked out by a team of doctors and health professionals often called a Multidisciplinary Team.

Doctors mainly use surgery, chemotherapy, and radiation therapy to treat colon cancer. They also sometimes use targeted therapy or immunotherapy.

A highly trained radiation oncology team takes care of people having radiation therapy. This includes radiation oncologists, radiation therapists, medical physicists and radiation oncology nurses.

Types of Radiation Therapy Used for Colon Cancer

External Beam Radiation Therapy (EBRT) is the most common type of radiation therapy used for colon cancer.

Radiation oncologists often use Volumetric Arc Therapy (VMAT) which is an advanced type of external beam radiation therapy, to carefully deliver radiation to the areas that need to be treated.

These advanced techniques allow the radiation oncologist to target the radiation on the cancer while limiting radiation to healthy parts of the body.

Doctors can often just use surgery to treat colon cancer especially if they find it early. Radiation therapy is not part of the usual treatment.

However, if there is a high chance of the cancer coming back, the doctors may also offer a person radiation therapy after surgery. Doctors also use chemotherapy after surgery to reduce the chances of the cancer coming back.

People get radiation therapy for colon cancer over a few weeks, with treatments given daily from Monday to Friday. The radiation oncology team works out the right number of treatments for each person.

Stereotactic Ablative Radiotherapy (SABR) for Colon Cancer

Radiation oncologists can use SABR to treat colon cancer that has spread to other parts of the body.

SABR is a targeted form of external beam radiation therapy. It gives high doses of radiation to the cancer while protecting healthy body parts. SABR is painless and no surgery is needed. It is very safe and effective.

For people with advanced colon cancer, radiation oncologists can use SABR to manage the cancer and reduce pain and other symptoms. People usually get 1-5 treatments.

In the interview below SABR expert Professor Shankar Siva explains how it works.

Play Video

SABR A Revolution in Radiation Therapy Interview with Professor Shankar Siva

General Information About Side Effects of Radiation Therapy

Radiation therapy is more effective with fewer side effects than ever before.

Recent advances mean radiation oncologists can effectively treat the cancer while getting less radiation on healthy body parts. This means much fewer side effects.

Side effects from radiation therapy vary between people, even for those having the same treatment.

While some people feel no side effects, some feel mild side effects, such as tiredness or skin redness during and/or just after treatment. These usually get better within a few weeks.

The treatment team will offer advice and medicine to help with side effects.

Serious side effects that start later (months to years after the radiation therapy) are rare.

Before starting treatment, your radiation oncologist will talk to you about side effects and answer your questions.

The side effects of radiation treatment can be split into 2 groups:

  1. Early side effects which occur during and shortly after radiation treatment.
  2. Late side effects which can occur months to years after radiation treatment.

For more information, go to the Potential Side Effects page.

Early side effects of radiation therapy may include:

Tiredness: People often feel more tired during and after treatment.

Diarrhoea: Radiation can cause loose or watery poo

Urinary discomfort: Radiation therapy can cause discomfort or a need to pee more often.

These side effects are usually short term and can be helped with medications or lifestyle changes. The treatment team can provide advice to help you manage side effects.

Late side effects vary between people and can happen a few months to a few years after treatment.

These side effects may never occur, occur once, continue over time, or come and go.

Bowel problems: Radiation therapy can cause long-term bowel issues such as diarrhea, constipation, or changes in bowel habits.

Bowel damage: Very rarely radiation therapy may cause a small bowel blockage, bleeding, a hole in the wall of the bowel and/or poor absorption of nutrients.

Fibrosis: Very rarely bowel tissue may become less stretchy and harden.

Urinary problems: Radiation therapy may cause long-term urinary problems, such as needing to pee more often or more urgently. Rarely it causes incontinence.

Second cancers: There is an extremely small risk of developing secondary cancers later in life.

People treated for colon cancer should see their doctor often and keep an eye out for long-term side effects.

Find additional information about cancer types, research groups, and support groups.

Further Information
You can ask your Surgeon or General Practitioner for a referral to a Radiation Oncologist for a discussion about whether radiation therapy is a suitable treatment option for you.

Radiation Oncologist

The best person to talk to is a radiation oncologist. You can ask your doctor for a referral to find out if radiation treatment is right for you.

GPs and Health Professionals

Information for any health professional involved in a patient's cancer care with a particular focus on primary care providers.

Talking to Your Doctor

Your GP or other doctors in the cancer team can organise a referral to a radiation oncologist.

Treatment Centres

Search and find your closest Radiation Oncology Treatment Centre.

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