When bowel cancer has spread to the liver, lung or lining of the abdomen and pelvis (omentum and peritoneum), this is known as advanced or metastatic (stage 4) bowel cancer. To control the cancer, slow its growth and manage symptoms such as pain, you may have a combination of chemotherapy, targeted therapy, radiation therapy and surgery.
Advanced bowel cancer is commonly treated with drugs that reach cancer cells throughout the body. This is called systemic treatment, and includes chemotherapy 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.
Monoclonal antibodies are the main type of targeted therapy drug used in Australia for advanced bowel cancer. They include:
This drug stops the cancer developing new blood cells and growing. It is given as a drip into a vein (intravenous infusion) every two to three weeks, with chemotherapy.
Cetuximab and panitumumab
These drugs target specific features of cancer cells known as epidermal growth factor receptors (EGFR). They only work for people who have a normal RAS gene (known as RAS wild-type). The tumour will be tested for changes (mutations) in these genes before you are offered these drugs. These drugs are usually given as a drip into a vein (intravenous infusion). They may be given with chemotherapy or on their own after other chemotherapy drugs have stopped working.
Other types of targeted therapy drugs may be available on a clinical trial. Talk with your doctor about the latest developments and whether you are a suitable candidate.
Scans and blood tests will be used to monitor your response to systemic treatments. If results show that the cancer is shrinking or is under control, chemotherapy and/or targeted therapy will continue. If the cancer is growing, that treatment will stop and alternative treatments will be discussed.
Side effects of targeted therapy
The side effects of targeted therapy vary depending on the drugs used. Common side effects of bevacizumab include high blood pressure, tiredness, bleeding and headaches. The most common side effects of cetuximab and panitumumab are skin problems (redness, swelling, an acne-like rash or dry, flaky skin), tiredness and diarrhoea. See Understanding Targeted Therapy.
Radiation therapy can also be used as a palliative treatment for both advanced colon and advanced rectal cancer. It can be used to stop bleeding and, if the cancer has spread to the bone or formed a mass in the pelvis, it can reduce pain. See further details.
If the cancer has spread to other parts of the body, you may still be offered surgery. This can help remove some secondary cancers (e.g. in the liver or lungs) or relieve a bowel obstruction.
You may have surgery to remove parts of the bowel along with all or part of other affected organs. This may be called an en-bloc resection or, if the cancer is in your pelvis, an exenteration.
If the cancer has spread to the lining of the abdomen (peritoneum), you may have surgery to remove as many tumours as possible. This is known as a peritonectomy or cytoreductive surgery. Sometimes, a heated chemotherapy solution is inserted into the abdomen during a peritonectomy. This is called hyperthermic intraperitoneal chemotherapy (HIPEC). Recent studies suggest that surgery alone may be as effective as surgery followed by HIPEC, and ongoing research continues to test the best approach to treatment.
The type of operation used for advanced bowel cancer will depend on your situation, so talk to your surgeon about what to expect. Your medical team will advise what kind of follow-up and treatment is recommended after surgery. Regular check-ups have been found to improve survival for people after surgery for bowel cancer, so you should have check-ups for several years.
Many treatments for advanced bowel cancer are best performed in a specialised centre. Call 13 11 20 for more information or to ask about assistance that may be available if you have to travel a long way.
If the cancer cannot be removed with surgery, but has only spread to a small number of places in a single area, your doctor may recommend another type of treatment to destroy or control the cancer. These treatments, including thermal ablation, selective internal radiation therapy (SIRT) and stereotactic body radiation therapy (SBRT), are only suitable for some people. They are best performed in a specialised centre or may be offered as part of a clinical trial.
Palliative treatment helps to improve people's quality of life by managing the symptoms of cancer without trying to cure the disease. It is best thought of as supportive care.
Many people think that palliative treatment is for people at the end of their life, but it may help at any stage of advanced bowel cancer. It is about living for as long as possible in the most satisfying way you can.
Sometimes treatments such as surgery, chemotherapy, radiation therapy or targeted therapy are given palliatively. The aim is to help relieve symptoms such as pain or bleeding by shrinking or slowing the growth of the cancer.
Palliative treatment is one aspect of palliative care, in which a team of health professionals aim to meet your physical, emotional, practical, social and spiritual needs. See Understanding Palliative Care and Living with Advanced Cancer.
Key points about advanced bowel cancer
What it is
Advanced bowel cancer is cancer that has spread from the bowel to another part of the body or come back after the initial treatment.
Treatment aims to control the cancer, slow down its spread and manage any symptoms.
The main treatment
Systemic treatments, including chemotherapy and targeted therapy, are used to control the cancer's growth and stop it spreading.
Monoclonal antibodies are the main type of targeted therapy drug used for advanced bowel cancer. They include bevacizumab, cetuximab and panitumumab. The tumour may need to be tested to see if these drugs will be effective.
Other treatment options
Other options might include chemotherapy, radiation therapy, surgery, and palliative treatments. For some people, the best option may be to join a clinical trial.
Treatment side effects
All treatments can cause side effects, such as pain, tiredness, skin problems or diarrhoea. Talk to your doctor about how to manage any side effects.
Expert content reviewers:
A/Prof Craig Lynch, Colorectal Surgeon, Peter MacCallum Cancer Centre, VIC; Prof Tim Price, Medical Oncologist, The Queen Elizabeth Hospital, Adelaide, and Clinical Professor, Faculty of Medicine, The University of Adelaide, SA; Department of Dietetics, Liverpool Hospital, NSW; Dr Hooi Ee, Gastroenterologist, Sir Charles Gairdner Hospital, WA; Dr Debra Furniss, Radiation Oncologist, Genesis CancerCare, QLD; Jocelyn Head, Consumer; Jackie Johnston, Palliative Care and Stomal Therapy Clinical Nurse Consultant, St Vincent's Private Hospital, NSW; Zeinah Keen, 13 11 20 Consultant, Cancer Council NSW; Dr Elizabeth Murphy, Head, Colorectal Surgical Unit, Lyell McEwin Hospital, SA.