Bowel cancer

What is bowel cancer?

Bowel cancer is the third most common cancer affecting Australians. It is estimated around 15,700 people are diagnosed with bowel cancer every year. It is most common in people over 50, but it can occur at any age.

In its early stages, bowel cancer may have no symptoms, but if detected early, it can be successfully treated.

A lot can happen in a hurry when you’re diagnosed with cancer. The guide to best cancer care for bowel cancer can help you make sense of what should happen. It will help you with what questions to ask your health professionals to make sure you receive the best care at every step.

How bowel cancer develops

The colon and rectum together are known as the large bowel. Bowel cancer usually affects the large bowel. Cancer of the large bowel is also known as colorectal cancer and might be called colon cancer or rectal cancer, depending on where it starts in the bowel.

Small bowel cancer is a rare type of cancer.

Illustration above adapted from original illustration, courtesy of the Cancer Council Victoria.

The bowel is part of the digestive system. The digestive system starts at the mouth and ends at the anus. It helps the body break down food and turn it into energy. It also gets rid of the parts of food the body does not use.

The bowel is the long ‘tube’ that absorbs water and nutrients from food and processes waste products into faeces (poo).

The development of bowel cancer starts in the inner lining of the bowel wall. If untreated, bowel cancer can grow into the deeper layers of the bowel wall. From there, it can spread to lymph nodes in the area and nearby organs such as the prostate or bladder. Later, bowel cancer can spread to the liver or lungs.

Bowel cancer usually develops from small growths called polyps. Most polyps are harmless (benign), but some may turn into cancer. To prevent this, polyps can be removed during a colonoscopy.

Symptoms of bowel cancer

Bowel cancer can develop with no symptoms. So, it is important to participate in screening.

Symptoms may include:

• Blood in your poo or on the toilet paper
• A change in your bowel habits, such as diarrhoea, constipation or smaller more frequent bowel movements
• Feeling like you need to poo more often or the feeling of incomplete emptying
• Feeling full or bloated in your belly or a strange sensation in the rectum, often during a bowel movement
• A change in the appearance of your poo (such as thin stools)
• Losing weight for no obvious reason
• Weakness or fatigue
• Anal or rectal pain
• A lump in the anus or rectum
• A low red blood cell count (anaemia or iron deficiency), which can cause tiredness or weakness
• Abdominal (stomach) pain or swelling
• A blockage in the bowel.

Having these symptoms does not mean that you have bowel cancer. People experiencing these symptoms should speak to their doctor.

Bowel cancer risk factors

The causes of bowel cancer are not known. Regular screening is important because bowel cancer can develop without noticeable symptoms.

The risk of bowel cancer is greater if you:

• Are aged 50 and over (risk increases with age)
• Have had an inflammatory bowel disease (such as Crohn’s disease or ulcerative colitis), particularly if you have had it for more than 10 years
• having a large number of polyps in the bowel
• Have a significant family history of bowel cancer or polyps
• Carry extra weight or are not physically active
• Have a diet high in red meat, especially processed meats (such as salami, ham, bacon, sausages)
• Drink alcohol or smoke
• Have a strong family history (a small number of bowel cancers run in families)
• Have had bowel cancer before. Some people who have had ovarian cancer or cancer of the uterus (endometrial cancer) may also have an increased risk
• Have a rare genetic disorder (a small number of bowel cancers are associated with an inherited gene).

If you are worried about your risk of bowel cancer, speak to your GP (doctor).

Bowel cancer in families

The risk of developing bowel cancer may be higher if one or more of your close family members (such as a parent, brother or sister) has had bowel cancer. The risk is higher if they were diagnosed before the age of 55, or if two or more close relatives on the same side of your family have had bowel cancer. A family history of some other cancers, such as cancer of the uterus (endometrial cancer), may also increase the risk.

Some people have an inherited faulty gene that increases their risk of developing bowel cancer. These faulty genes cause a small number (about 5–6%) of bowel cancers. There are two main genetic conditions that occur in some families:

• Familial adenomatous polyposis (FAP) – This condition causes hundreds of polyps to form in the bowel. If these polyps are not removed, they may become cancerous.
• Lynch syndrome – This syndrome causes a fault in the gene that helps the cell’s DNA repair itself. People with Lynch syndrome have an increased risk of developing bowel cancer, cancer of the uterus, and other cancers such as kidney, bladder and ovarian.

If you are worried about your family history, talk to your doctor about having regular check-ups or ask for a referral to a family cancer clinic.

Types of bowel cancer

Most bowel cancers are adenocarcinomas. This means they start in the tissue lining the bowel. Other rare types include:

• squamous cell cancers (in the skin like cells of the bowel lining)
• neuroendocrine tumours (NETs)
• small bowel cancer
• gastrointestinal stromal tumours
• lymphomas.

Diagnosis of bowel cancer

Several tests can be used to diagnose bowel cancer including:

• Physical and rectal examination.
• Blood tests – including a carcinoembryonic antigen (CEA) test and immunochemical faecal occult blood test (iFOBT).
• Colonoscopy and biopsy.
• PET-CT scan.
• CT scan.
• MRI scan.
• Molecular testing – may be used with a diagnosis of advanced bowel cancer to check the biopsy sample for gene mutations or other cell features. If this is the case, further genetic testing may be required.
• CT colonography.
• Flexible sigmoidoscopy.

Waiting for test results

Test results may take a few days to come back. It is natural to feel anxious waiting to get your results. It can help to talk to a close friend or relative about how you’re feeling. You can also contact Cancer Council on 13 11 20 and speak with a cancer nurse.

Bowel cancer stages

Knowing if and how far the cancer has spread is called ‘staging’ the disease. Staging helps your doctor work out the best treatment for you.

In Australia, the staging system for bowel cancer is the TNM system, which stands for tumour-node-metastasis, which gives numbers to:

• the size of the tumour (T1—4)
• whether or not lymph nodes are affected (N1—2)
• whether the cancer has spread or metastasised outside the bowel (M0-M1)

The Australian Clinico-Pathological Staging (ACPS) system may also be used in some hospitals.

Based on the TNM numbers, the doctor then works out the cancer’s overall stage:

• stage 1: tumour is found only in the inner layers of the bowel wall
• stage 2: tumour has spread deeper into the layers of the bowel wall
• stage 3: tumour is in any layer of the bowel wall and has spread into nearby lymph nodes
• stage 4: tumour has spread beyond the bowel to other parts of the body, such as the liver or lungs, or to distant lymph nodes.

Around half of all bowel cancers in Australia are diagnosed at stage 1 or 2.

Ask your doctor to explain the stage of your cancer in a way you can understand. This will help you to choose the best treatment for your situation.

Treatment for bowel cancer

Your health care team will recommend treatment based on:

• what will give you the best outcome
• where the cancer is in the bowel
• whether and how the cancer has spread
• your general health
• your preferences.

Surgery

Surgery is the main treatment for bowel cancer. The aim of surgery is to remove as much of the cancer as possible and nearby lymph nodes.

Surgery may be performed as keyhole or open surgery.

The most common type of surgery is a colectomy – where a part of the bowel, lymph nodes near the colon and some normal bowel around the cancer is removed.

The surgeon removes the section of the bowel affected by cancer and then joins the two ends. If the end is made from the large bowel it is called a colostomy. If it is made from the small bowel it is called an ileostomy.

Colostomy (made from the colon)

Ileostomy (made from the ileum)

Types of stomas, courtesy of Cancer Council Victoria.

A stoma (an opening of the bowel onto the abdomen) is sometimes made during the surgery. Your bowel motions (poo) will come through the stoma into a bag.

Some stomas are temporary – to allow the bowel to heal, while others are permanent. Around 1 in 10 people with rectal cancer need a permanent stoma.

Before your surgery, you will be given a lot of education and support about having a stoma.

Chemotherapy and radiotherapy

Chemotherapy or radiotherapy (also known as radiation therapy) may be used in addition to surgery.

Radiation therapy is often used before surgery and may be used with chemotherapy to reduce the size and number of cancer cells.

Radiation therapy is not used for early colon cancer.

Occasionally, if the cancer is more advanced, radiation therapy may be used after surgery to destroy any remaining cancer cells.

If the cancer has spread outside the bowel to lymph nodes or to other organs, chemotherapy may be recommended:

• Before surgery – to shrink the tumour and make it easier to remove.
• After surgery – to kill any remaining cancer cells and reduce the chance of the cancer coming back.
• On its own – if the cancer has spread to other organs.

Your doctor will discuss your treatment in detail with you.

Systemic treatment

Advanced bowel cancer is commonly treated with drugs that reach cancer cells throughout the body. This is called systemic treatment, and includes chemotherapy, immunotherapy and targeted therapy.

Targeted therapy drugs work differently from chemotherapy drugs. While chemotherapy drugs affect all rapidly dividing cells and kill cancerous cells, targeted therapy drugs affect specific molecules within cells to block cell growth.

Immunotherapy uses the body’s own system to fight cancer. Checkpoint inhibitors are the main type of immunotherapy drug used for the small number of advanced bowel cancers that have a fault in the mismatch repair (MMR) gene. How many infusions you receive will depend on how you respond to the drug (pembrolizumab).

Complementary therapies

Complementary therapies are designed to be used alongside conventional medical treatments (such as surgery and radiation therapy). They can increase your sense of control, decrease stress and anxiety, and improve your mood.

It is important to tell your treating team about any complementary medicines you are taking. Never stop taking your conventional treatment without consulting your doctor first.

Side effects of bowel cancer treatment

All treatments have side effects. These will vary depending on the type of treatment you are having. Many side effects are temporary, but some may be permanent. Your doctor will explain all the possible side effects before your treatment begins.

Radiation therapy to the pelvis and rectum can affect your sexual function and ability to have children (fertility). It is important to discuss your options with your doctors before you start treatment.

Some side effects can be upsetting and difficult, but there is help if you need it. Call Cancer Council 13 11 20 or contact cancer support to speak with a caring cancer nurse for support.

Living with a stoma

Most people find it takes time to come to terms with having a stoma. It is a big change in your life.

People often worry about how they will care for their stoma. A stomal nurse will explain how to care for your stoma and tell you about support services.

Sexuality and bowel cancer

Having bowel cancer and treatment can change the way you feel about yourself, other people, relationships and sex. These changes can be very upsetting and hard to talk about. Doctors and nurses are very understanding and can give you support. You can ask for a referral to a counsellor or therapist who specialises in body image, sex and relationships.

Living with advanced cancer

Advanced cancer usually means cancer that is unlikely to be cured. Some people can live for many months or years with advanced cancer. During this time palliative care services can help.

Most people continue to have treatment for advanced cancer as part of palliative care, as it helps manage the cancer and improve their day-to-day lives.

Many people think that palliative care is for people who are dying but palliative care is for any stage of advanced cancer. There are doctors, nurses and other people who specialise in palliative care.

Treatment for advanced bowel cancer may include chemotherapy, radiation therapy, surgery or another type of treatment. It can help in these ways:

• slow down how fast the cancer is growing
• shrink the cancer
• help you to live more comfortably by managing symptoms, like pain.

Treatment depends on:

• where the cancer started
• how far it has spread
• your general health
• your preferences and what you want to do.

Ask your doctor about treatment and palliative care services that may help you.

Caring for someone with bowel cancer

Caring for someone with cancer can be a difficult and emotional time. If you are caring for someone with bowel cancer, these organisations can help:

• Cancer Council Victoria 13 11 20
• Carer Gateway 1800 422 737
• Carers Australia 1800 242 636

Reducing your risk of bowel cancer

For people aged 45 to 74 and at average risk of bowel cancer, having regular screening for bowel cancer is the most effective way to reduce your risk of bowel cancer.

You can also help to reduce your risk of bowel cancer by:

• eating a healthy diet with plenty of fresh vegetables and fruit
• limiting your consumption of red meat and processed meats
• maintaining a healthy body weight
• daily physical activity
• quitting smoking
• reducing your alcohol intake.

Following this advice doesn’t mean that you will never get bowel cancer, but it can reduce your risk and has other health benefits too.

Screening for bowel cancer

Screening is the process of looking for cancer, or abnormalities that could lead to cancer, in people who do not have any symptoms. It is particularly important for bowel cancer, which often has no symptoms in its early stages.

The National Bowel Cancer Screening Program (NBCSP) sends free at-home bowel cancer screening test to all eligible Australians aged 50 to 74, every 2 years. People ages 45 to 49 can request their first kit at the National Cancer Screening Register website or call 1800 627 701. All eligible people aged 45 to 74 can also ask their doctor about getting a free test kit.

A test kit can also be purchased from some pharmacies.

The screening test used is called the faecal occult blood test (iFOBT). This involves taking tiny samples from two separate bowel motions (poo) using a test kit. The samples are then posted to a laboratory for testing.

If blood is detected, the doctor is likely to refer you for a colonoscopy. Most positive tests are not the result of cancer. However, if cancer is detected early, there is a higher chance of it being treated successfully.

You can access more information about bowel cancer screening from the national Department of Health and the Indigenous Bowel Screen websites.

Where to get help

• Your GP (doctor)
• Your cancer specialist (oncologist)
• Your treatment team
• Cancer Council Victoria Tel. 13 11 20 (to speak to someone in a language other than English call 13 14 50 and ask to speak to Cancer Council)
• Cancer Council Victoria, My Cancer Guide - Find support services that are right for you.