Targeted therapies and immunotherapies for bowel cancer
Targeted therapies are sometimes used to treat bowel cancers that have spread to other parts of the body (secondary bowel cancer). Immunotherapy drugs are only available as part of a clinical trial.
Targeted therapy drugs target something in or around a cancer cell that is helping it grow and survive.
Your doctor will tell you if they think a targeted therapy will be helpful in your situation. These drugs are not always available through the NHS. If a drug is not available on the NHS, there may be different ways you can still have it. Your doctor can give you advice. They may be able to apply for funding to get the treatment on the NHS.
Cetuximab and panitumumab
Some cancers have receptors on their surface called epidermal growth factor receptors (EGFRs). A protein called epidermal growth factor activates the receptors, causing the cancer cells to grow. Cetuximab and panitumumab lock onto the EGFRs and block signals that tell the cancer cells to grow and divide.
Before cetuximab or panitumumab are used, doctors test the cancer cells for cell changes (mutations) in the RAS and BRAF gene. This helps your doctor decide if cetuximab or panitumumab is appropriate for you.
Not all bowel cancers respond to cetuximab and panitumumab. They only work on bowel cancers that have a normal RAS gene and no changes to the BRAF gene. Cetuximab and panitumumab are given into a vein as an infusion (intravenously). You often have them with chemotherapy.
Other targeted therapy drugs
Other targeted therapy drugs that may be used include:
- bevacizumab (Avastin®)
- aflibercept (Zaltrap®)
- ramucirumab (Cyramza®)
- regorafenib (Stivarga®).
These are all a type of targeted therapy called angiogenesis inhibitors.
These block the chemical signals that cells use to make blood vessels grow. This makes it difficult for a tumour to develop the network of blood vessels it needs to get a blood supply. Without a good blood supply, the tumour does not get the oxygen and nutrients it needs. This may slow the tumour’s growth, or sometimes cause it to shrink.
Bevacizumab, aflibercept and ramucirumab are given into a vein as an infusion (intravenously). Regorafenib is taken as tablets.
Some targeted therapies can cause an allergic reaction. This may happen when the drug is being given or shortly after.
Signs of an allergic reaction can include:
- flu symptoms
- a sudden drop in blood pressure
- feeling sick.
An allergic reaction is most common with the first two of doses of the drug, but can happen later. To reduce this risk, you will have the first dose over a few hours. Your nurse will closely monitor you during the infusion.
Your doctor or nurse should tell you about possible side effects before you start treatment. They will also tell you who you should contact if you develop any.
The most common side effect of bevacizumab, aflibercept, ramucirumab and regorafenib is high blood pressure. There is also a small risk they may cause a hole (perforation) in the bowel.
If you have any side effects during cancer treatment, you should always tell your cancer doctor or specialist nurse.
Immunotherapy drugs encourage the immune system to recognise and help destroy cancer cells. Immunotherapy drugs for bowel cancer are not regularly used by, or available on, the NHS. They are only available as part of a clinical trial.
Talk to your cancer doctor or specialist nurse for more information about immunotherapy.
Your cancer doctor may consider immunotherapy if both of these things apply:
- the cancer has spread to other parts of the body
- the cancer shows changes (mutations) to DNA called microsatellite instability (MSI).
Your cancer doctor will talk with you if immunotherapy may be option for you.
Below is a sample of the sources used in our bowel cancer information. If you would like more information about the sources we use, please contact us at firstname.lastname@example.org
R Glynne-Jones, PJ Nilson, C Aschele et al. ESMO-ESSO-ESTRO Clinical practice guidelines for diagnosis, treatment and follow up for anal cancer. July 2014. European Society of Medical Oncology. Available from www.esmo.org/Guidelines/Gastrointestinal-Cancers/Anal-Cancer (accessed October 2019).
National Institute for Health and Excellence (NICE). Colorectal cancer: diagnosis and management clinical guidelines. Updated December 2014. Available from www.nice.org.uk/guidance/cg131 (accessed October 2019).
Association of Coloproctology of Great Britain & Ireland (ACPGBI). Volume 19. Issue S1. Guidelines for the management of cancer of the colon, rectum and anus. 2017. Available from www.onlinelibrary.wiley.com/toc/14631318/19/S1 (accessed October 2019).
BMJ. Best practice colorectal cancer. Updated 2018. Available from www.bestpractice.bmj.com/topics/en-gb/258 (accessed October 2019).
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.
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