The colon is part of the large bowel, which is part of the digestive system. Colon cancer is more common in older people. In the UK, almost 6 in 10 bowel cancer cases (58%) each year are diagnosed in people aged 70 and over.
We have more information about other types of bowel cancer including:
Some people start by seeing their GP after experiencing symptoms. But there are other ways you may be diagnosed:
Having NHS Bowel Screening
Going to hospital with a problem, such as bowel obstruction
This is when part of the bowel becomes blocked. It may cause symptoms such as tummy pain, nausea and vomiting, and constipation.
If you are worried about colon cancer, we have more information about the signs and symptoms. If you have any symptoms or notice anything that is unusual for you see your GP straight away.
Doctors do not know the exact causes of colon cancer. But there are risk factors that can increase your chance of developing it.
Having one or more risk factors does not mean you will get colon cancer. Also, having no risk factors does not mean you will not develop colon cancer.
We have more information about the causes and risk factors of bowel cancers.
If you have symptoms, you usually begin by seeing your GP. If they think that your symptoms could be caused by cancer, you should see a specialist at the hospital within 14 days.
At the hospital you will usually have:
You may then have the following tests:
Colonoscopy – this is the main test for colon cancer
Waiting for test results can be a difficult time, we have more information that can help.
Further tests for colon cancer
If any of your biopsies show that there is cancer in the colon, you will have more tests. These are to find out more about the cancer. The results help your doctors plan your treatment. You may also have some of these tests again during and after treatment:
More blood tests
Your blood may be tested for a protein called carcinoembryonic antigen (CEA). Some people with bowel cancer have higher levels of this protein. Your doctors may check it regularly to see how well your treatment is working.
MRI (magnetic resonance imaging) scan
A PET-CT scan is a combination of a CT scan, which takes a series of x-rays to build up a three-dimensional picture, and a positron emission tomography (PET) scan. A PET scan uses low-dose radiation to measure the activity of cells in different parts of the body.
The results of your tests help your doctors find out more about the size and position of the cancer and whether it has spread. This is called staging.
A doctor decides the grade of the cancer by how the cancer cells look under the microscope. This gives an idea of how quickly the cancer might grow or spread.
Knowing the stage and grade helps your doctors plan the best treatment for you.
A team of specialists will meet to discuss the best possible treatment for you. This is called a multidisciplinary team (MDT).
Your cancer doctor or specialist nurse will explain the different treatments and their side effects. They will also talk to you about things to consider when making treatment decisions.
Surgery is the most common treatment for colon cancer. But the treatment you have depends on the stage of the cancer and where it is in the colon. It also depends on your general health and preferences. You can read an overview of treatment options for colon cancer here.
Treatment may include:
You may have some treatments as part of a clinical trial.
Most people have changes in how their bowel works after treatment for colon cancer. These effects usually improve over time. We have more information about managing bowel changes caused by treatment.
Follow-up after treatment for colon cancer
The aim of follow-up care is to make sure everything is going well and to find out if you have any concerns. The appointments are usually every few months in the first year.
We have more information on follow-up care after treatment.
Colon cancer and its treatment can affect your sex life. Changes may get better over time, but sometimes they are permanent. If you have any problems or are worried about this talk to your doctor or nurse. They can explain what to expect and there are often things that can help.