Colorectal cancer (bowel cancer)
Information for patients from the Association of Coloproctology of Great Britain and Ireland (ACPGBI)
Colonic cancer can occur anywhere in the colon. The cells that line the colon may become damaged, such that they begin to divide in an uncontrolled way. This may lead to the formation of a polyp or eventually a cancer. Colonic cancer is:
the third most common cancer in men in the UK;
the second most common cancer in women in the UK; with
42,000 cases diagnosed each year.
What are the symptoms?
Common symptoms include the following.
Bleeding from the back passage.
A change in how often you pass stools (poo).
Abdominal (tummy) pain.
Weight loss and poor appetite.
However, the above symptoms are very common and are usually not due to colonic cancer.
How is the diagnosis made?
To diagnosis colonic cancer it is essential to examine the colon. We do this either with:
a flexible telescope (flexible sigmoidoscopy or colonoscopy); or
a special test called a CT colonoscopy (CTC).
If we find a cancer during a colonoscopy, we take a tiny portion of tissue (biopsy) from the cancer. The tissue is then sent for laboratory examination. A tattoo is often placed to identify the site of the suspected tumour. We will also arrange a CT scan, to examine the lungs and liver to check that the cancer has not spread.
How can it be treated?
The best chance of curing colonic cancer is with an operation. This operation aims to remove the segment of colon with the cancer in it, along with the blood supply and lymph nodes (glands) that supply it. The type of operation will depend on the location of the cancer.
Right hemicolectomy involves removing the appendix and colon on the right side of the body. We then join the small bowel back to the colon, so that the bowel works normally.
Left hemicolectomy or sigmoid colectomy involves removing the colon on the left side of the body. We then join the bowel back together, so that the bowel works normally.
Subtotal colectomy involves removing the whole colon and usually joining the small bowel to the rectum.
These are the most common types of operations, but your surgeon may discuss others with you. Please use this time to ask your surgeon any questions.
Your surgeon can carry out these operations with:
a single large incision (open surgery); or
multiple small incisions (keyhole or laparoscopic surgery).
The way in which the operation is performed depends on factors relating to you, the cancer, and your surgeon. It also depends on whether robotic-assisted surgery is an option for you.
Your surgeon will discuss all your options with you, and explain the operations fully. Please use this time to ask any questions you may have. Remember you can withdraw your consent for treatment at any time.
Is a stoma necessary?
A stoma (colostomy) is an artificial opening of the colon on to the abdominal wall. It is not always necessary in these operations. Your surgeon will discuss with you the possibility of needing a stoma. Many people live a full and active life with a stoma. However, it may seem worrying and you will receive all the support needed to make sure you are fully prepared.
Are there any other forms of treatment?
Chemotherapy and / or immunotherapy. Once you have recovered from your surgery and the pathologist has examined the cancer, we may recommend a course of chemotherapy. This will depend upon your general state of health and the stage of the cancer.
The stage of cancer gives an indication as to whether the cancer has spread to other organs (usually the glands close to the bowel, the liver, or lungs). We assess the stage of cancer using a combination of:
the tests that you had before your operation (CT scans); and
the pathologist’s opinion after they have examined the cancer under the microscope.
If chemotherapy is recommended, you can discuss it further with a specialist in this field called an oncologist.
Liver surgery. If the cancer has spread to the liver it may still be possible to attempt to cure the cancer. We do this by removing part of the liver during an operation. If your surgeon recommends this surgery, you can discuss it further with a specialist in this field. The specialist is called a hepatobiliary surgeon.
Colostomy. Some cancers can cause a blockage to the bowel. Your surgeon may recommend a colostomy to prevent this. This is more likely if you are very frail or the cancer has spread to many other organs.
Before any decisions are made, we will discuss all treatment options with you and the people important to you (with your permission).
What if I decide not to have surgery?
If you decide surgery is not right for you, we are still here to support you. We will help manage symptoms, try to improve your quality of life, and provide pain relief. If you have any questions or concerns about your options, please speak to your surgeon.
What are the chances of a cure?
Appropriate surgery offers the best chance of a cure. Possibly combined with chemotherapy and / or immunotherapy. The earlier we find the cancer and treat it, the more likely the cure.
In early cancers the cure rate is greater then 90%.
In cancers at a more advanced stage, the chances of a cure are less than 50%.
Will I need to be seen again?
Yes. We will check you on a regular basis following your treatment. How often we do this will depend on the stage of cancer, and will be tailored to your own particular needs. This will usually include visits to the clinic, CT scans, and colonoscopy.
Further information
References
[Websites last accessed 27 January 2026]
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Produced with grateful acknowledgement to The Association of Coloproctology of Great Britain and Ireland (ACPGBI).