Bowel cancer is cancer in any part of the colon or rectum. Bowel cancer can develop in two ways: it can grow from the inner lining of the bowel, or from small growths on the bowel wall called polyps. These mushroom-shaped growths are usually harmless (benign) but may become cancerous over time.

If untreated, bowel cancer can spread (metastasise) deeper into the wall of the bowel. From there it can spread to the lymph nodes (glands).

Lymph nodes are small, bean-shaped masses that collect and destroy bacteria and viruses in the body. They are part of the body’s lymphatic system, which plays an important role in the functioning of the immune system.

Later, bowel cancer can spread to other organs such as the liver or lungs. In most cases, it develops fairly slowly and may stay in the bowel for months or years before spreading.

The colon and rectum together are known as the large bowel. The word colorectal is commonly used to describe cancers of the colon or rectum. Bowel cancer is also called colorectal cancer. The terms large intestine, large bowel and colon all refer to the same organ.

Staging bowel cancer

The tests described in the Diagnosis article help determine whether you have bowel cancer. Some tests also show if the cancer has spread to other parts of the body. This is called staging. It helps your doctors work out the best treatment for you.

There are different staging systems used to stage bowel cancer. In Australia, the most common staging system used is called the Australian Clinico-Pathological Staging (ACPS) system. This is described below.

Stage A Cancer is found only in the bowel wall.
Stage B Cancer has spread to the outer surface of the bowel wall.
Stage C Cancer has spread to the lymph nodes near the bowel.
Stage D Cancer has spread beyond the lymph nodes to other areas of the body such as the liver or lungs.

Another staging system being used more often is called the TNM system. It shows how far the tumour (T) has spread into the bowel wall, if lymph nodes are affected (N) and if the cancer has spread (metastasised) to other parts of the body (M). In the TNM system, each letter is assigned a number that indicates how advanced the cancer is.

You may also hear about the Dukes system, which is an older staging system similar to the ACPS.



The main treatment for bowel cancer is surgery. You may also have chemotherapy or radiotherapy. You may only need one type of treatment, but sometimes you may have a combination.


There are different types of surgery for bowel cancer. Which one you have depends on where the cancer is in the bowel, the type and size of the cancer and whether it has begun to spread. The doctor will also consider your age and general health.

Minimally invasive surgery

The term minimally invasive surgery, also called keyhole or laparoscopic surgery, means a surgical technique that involves several small cuts (incisions) instead of one large cut on the abdomen.

The surgeon passes a thin, flexible tube called a laparoscope through one of the cuts. The laparoscope is fitted with a light and camera so the surgeon can see into the abdomen and remove the cancer. This technique usually means less pain and scarring, a lower risk of infection and a faster recovery with less time spent in hospital.

Minimally invasive bowel surgery is often recommended for early stage cancers and if the surgeon is confident the tumour can be easily removed. This depends on the location of the cancer and its size.

Ask your surgeon if this type of surgery is suitable for you and if it is available at your hospital or treatment centre.

Surgery for colon cancer

The most common type of colon cancer surgery is called a colectomy. There are different types of colectomies depending on where in the bowel the tumour is located.

Before the surgery, the operation and what to expect afterwards will be explained to you. Some people have minimally invasive surgery (see page 25) instead of the procedure described here.

The surgeon will make a cut in the abdomen to remove the part of the colon containing the cancer. The lymph nodes near the colon are also removed. The surgeon joins the two ends of the colon back together.

Sometimes, to allow the area time to heal, the bowel isn’t joined but is brought out onto an opening on the outside of the body. This procedure is called a colostomy and the opening is called a stoma. Another operation to rejoin the bowel can be done a few months later. In some cases, the surgeon will be unable to rejoin the ends of the colon and will connect the large bowel to a permanent stoma. For information about temporary and permanent stomas, see pages 41–44.

After surgery you will have a scar, usually running from your navel to your pubic area. See pages 31–33 for information about recovering from surgery and details about dietary changes you may have to make.

Surgery for rectal and anal cancers

If you have rectal or anal cancer, you may have part of the bowel removed, known as a resection. There are different types of resections depending on where in the rectum the cancer is located.

Anterior resection

The surgeon cuts out cancerous tissue in the rectum. You may have one large cut in your abdomen, or if your surgeon uses the minimally invasive technique, you will have small cuts. The type of surgery you have will depend on your situation.

During an anterior resection, the left part of the colon and the upper part of the rectum are removed, together with its blood supply and nearby lymph nodes. The ends of your bowel are rejoined.

Ultra-low anterior resection

If you have an ultra-low anterior resection, the left part of the colon and the entire rectum will be removed. Your surgeon will then perform a coloanal anastomosis. This means that your colon is joined to your anus. In some cases the surgeon may also create an internal pouch (called a colonic J-pouch) using the lining of the large bowel. The J-pouch will be connected to the anus and will work as a rectum. You may have a temporary stoma, which will be reversed once your J-pouch is healed.

Abdominoperineal (AP) resection

An AP resection is a less common type of rectal surgery. In this procedure, the entire rectum and anus are removed. After an AP resection, you will have two wounds: one on your abdomen and one where your anus was removed.

Your doctor will also create a permanent stoma, and waste will be removed through this opening.

Local excision

This type of surgery is usually used for very early stage tumours. The surgeon removes the cancer without cutting into the abdomen. Instead, the surgeon inserts an endoscope, like the one used to take a biopsy, into the rectum and lower colon and cuts the cancer out.

There are several types of local excision. For example, if the surgeon cuts out a cancerous polyp, it is called a polypectomy. If a surgeon cuts out a tumour, it is called a transanal excision.

The type of surgery you have will depend on the location of the cancer. For example, if the cancer is in or near the anal sphincter muscles, a transanal resection is not suitable.

Surgery for advanced cancer

A small number of people will have two separate cancers in their large bowel at the same time. Doctors may find the cancers using diagnostic tests or during surgery.

In this case, there are three options for surgery:

The type of surgery you have depends on your doctors’ recommendations and what you want.

In some cases, the cancerous part of the large bowel will be attached to another organ, such as the uterus or bladder. This may be caused by inflammation or by the cancer spreading. Your surgeon may remove the attached organ and the large bowel. If you need this type of operation, talk to your surgeon about what to expect. For example, the removal of a woman’s uterus (hysterectomy) causes infertility, so it is important to talk to a doctor or a fertility counsellor before treatment. This person can help you address your feelings and explore your options.

After surgery you will need regular checkups for the rest of your life as the chance of developing another primary cancer is higher than average. For more information about surgery for advanced bowel cancer, call the Cancer Council Helpline on 13 11 20.


Chemotherapy is the treatment of cancer with anti-cancer (cytotoxic) drugs. The aim of chemotherapy is to kill cancer cells while doing the least possible damage to healthy cells.

If the cancer is contained inside the bowel, surgery is the only treatment needed and chemotherapy is not used.

Chemotherapy may be used for the following reasons:

Some people have chemotherapy after surgery. In most cases, you will have 6–8 weeks to recover from surgery, and you will start chemotherapy treatment when your wounds are healed.

Chemotherapy drugs are usually injected into a vein (intravenously) or sometimes given in tablet form. Some people have a small medical appliance called a port-a-cath or catheter placed beneath their skin through which they can receive chemotherapy. You will probably have sessions of chemotherapy over several weeks or months. Your medical team will work out your treatment schedule.

Refer to Cancer Council’s free Understanding Chemotherapy book for more details.

Side effects

The side effects of chemotherapy vary according to the drugs used. Your doctor will talk to you about these side effects and how to manage them.

Some of these side effects include tiredness, nausea, diarrhoea, mouth sores and ulcers, sore hands or feet, and a drop in levels of blood cells.

Most side effects are temporary and there are ways to prevent or reduce them. Tell your doctor or nurse about side effects you experience. They may prescribe medication to manage the side effects, arrange a break in your treatment, or change the kind of treatment you are having.

While having chemotherapy, you will be at a higher risk of getting an infection and bleeding in your bowel or other parts of your body. Tell your doctor if you are fatigued, or if you bruise or bleed easily. If you have a temperature over 38oC, contact your doctor or nurse immediately and go straight to the hospital emergency department.


Radiotherapy uses high-energy x-rays or electron beams to kill or damage cancer cells. Radiotherapy may be given before or after surgery for some people with rectal cancer, instead of surgery, or as palliative treatment (see page 38).

During treatment, you will lie under a machine that delivers x-ray beams to the treatment area. Each treatment only takes a few minutes once it has started, but setting up the machine and seeing the radiation oncologist during your first treatment session may take a few hours.

Radiotherapy is usually given once a day, Monday to Friday, for about 5–7 weeks. The number of radiotherapy treatments you have will depend on the site and extent of the cancer and your radiation oncologist’s recommendation.

Side effects

Radiotherapy can cause temporary or permanent side effects. Temporary side effects often appear during treatment, but some may last a few months after treatment or permanently. Some temporary side effects of radiotherapy include:

Your treatment team will advise you about how to manage side effects. For example, you will need to take care washing the treatment area and wear appropriate clothing and underwear to prevent rubbing or chafing. Ask a member of your radiotherapy treatment team what type of skin care products to use.

Effects on fertility

For men, radiotherapy to the pelvis may reduce sperm production or damage the sperm. This may be temporary or permanent. If you want to have children or are unsure what your plans are, you may be able to store sperm before treatment starts. Some doctors suggest that men try to avoid conceiving naturally for six months after radiotherapy treatments have finished.

For women, radiotherapy may lead to damage and shrinking of the vagina and premature menopause, which can cause infertility. You may feel devastated if you are no longer able to have children and may worry about the impact of this on your relationship. Even if your family is complete, you may have mixed emotions about experiencing menopause.

Talking to your partner, a counsellor or to a specialist about your options can help. You can also refer to the Cancer Council’s booklet, Sexuality, Intimacy and Cancer for more information.

  • 1. Remove the two small sections of the bowel.
  • 2. Remove one larger section of the bowel, containing both areas with cancer.
  • 3. Remove the entire colon and rectum (proctocolectomy) to prevent any chance of another cancer forming.
    • Neoadjuvant therapy – Some people who have surgery have chemotherapy (and/or radiotherapy, see page 36) beforehand to shrink the tumour and make it easier to remove during surgery.
    • Adjuvant chemotherapy – Chemotherapy is often recommended for people if the bowel cancer has spread through the bowel wall or into the lymph nodes but no further.
    • Reduce symptoms – If the cancer has spread to other organs, such as the liver or bones, chemotherapy may be used as palliative treatment (see page 38).
    • bleeding
    • diarrhoea
    • nausea
    • tiredness or fatigue
    • mild headaches
    • urinary or faecal incontinence (see page 40)
    • redness and soreness in the treatment area.

For further details on side effects and how to manage them call 13 11 20 for a free copy of Understanding Radiotherapy.

Palliative treatment

Palliative treatment helps to improve people’s quality of life by alleviating symptoms of cancer without trying to cure the disease. It is particularly important for people with advanced cancer. However, it is not just for people who are about to die and it can be used at different stages of cancer.

Often palliative treatment is concerned with pain relief and stopping the spread of cancer, but it can also involve the management of other physical and emotional symptoms. Treatment may include radiotherapy, chemotherapy or other medication.

For more information on palliative treatment or advanced cancer, call the Helpline for free copies of Understanding Palliative Care or Living with Advanced Cancer, or view them online at

Palliative treatment can help with pain and symptom management – it is not just for end-of-life care.

Last Reviewed: 01/02/2011

Reproduced with the kind permission of The Cancer Council New South Wales.


Cancer Council NSW. February 2011. Understanding Bowel Cancer. A guide for people with cancer, their families and friends. (accessed Jan 2013.)