When we swallow our food, it passes through the oesophagus and into the stomach. Here the food is broken down into smaller bits. The food then moves to the bowels (intestines), where the water and nutrients from the food are absorbed. The bowels include the small intestine and the large intestine (colon). What is left after passing through the bowels is stool, which is stored in the rectum until you poo.
Sometimes, the cells that make up the colon or the rectum can become malignant. This means that they do not work properly anymore and multiply uncontrollably, causing a tumour to grow. When this happens in the colon, this is called colon cancer. When this happens in the rectum, this is called rectal cancer. Because they are very similar, colon cancer and rectum cancer are grouped together as colorectal cancer, also known as bowel cancer.
Only a very few people who have had cancer before develop bowel cancer.
Due to treatment of the first cancer, survivors sometimes have a higher risk of bowel cancer. There are a number of things anyone can do to lower the risk of having bowel cancer, such as adopting or maintaining a healthy diet and weight.
Am I at higher risk of bowel cancer?
Anyone, including people who have never had cancer treatment, may develop bowel cancer. However, there are some cancer treatments that may increase the risk of having bowel cancer as a subsequent tumour later in life.
The following treatment can increase the risk of bowel cancer:
Radiotherapy to the colon and rectum or an area that includes the colon and rectum
You can find out if you have received radiotherapy to the colon or rectum by looking at your treatment summary. If you do not have a treatment summary or if you have any questions, do contact your treating hospital.
If you develop bowel cancer, it does not always mean that this is caused by treatment for your first cancer. Bowel cancer may have other causes, such as being overweight and obese, smoking, drinking (too much) alcohol. For more information on being overweight and obese, please read: Overweight and obesity. If you have had colon polyps in the past or if cancer at an unusually young age is common in your family, this may also increase your risk of having bowel cancer.
What are the symptoms and signs of bowel cancer?
There are symptoms and signs that can tell you if you might have bowel cancer. You might not have these symptoms and signs at the moment, but it is important to be aware of them in case they may develop in the future.
These symptoms and signs may suggest that you have bowel cancer:
Blood in the stool and/or bleeding from the rectum
The stool is abnormal or different from usual
Pooping more often or not being able to pass stool (constipation)
Pain, discomfort or feeling bloated after eating
Swelling of the tummy
Feeling nauseous and/or vomiting
Pain when passing stool
These symptoms and signs are often caused by something else. However, early diagnosis and treatment of colorectal cancer is very important. If you experience any of these symptoms or signs, please contact your general practitioner or follow-up care specialist soon.
I am at higher risk of bowel cancer. What tests should I have and when?
If you are at higher risk of bowel cancer, it is advised to have the regular tests after the age of 30 or 5 years after radiation treatment ended, whichever occurs last. You and your follow-up care specialist will discuss and jointly decide what the preferred follow-up care for you is (this is called shared-decision making). This may be:
Have your stool tested for blood every 3 years.
If you prefer, you can also choose to have a colonoscopy every 5 years. With this test, the doctor looks inside the bowel by inserting a tube with a small camera in the anus.
If you decide to have a colonoscopy every 5 years, your stool does not need to be tested every 3 years. If blood is found in your stool, this does not automatically mean you have bowel cancer. However, further investigations will be needed.
If bowel cancer runs in your family and you are worried that you may get it too, please inform your general practitioner or follow-up care specialist. If you want, they may request a genetic test that can tell if you have inherited one of the bowel cancer genes.
What happens if I (might) have bowel cancer?
If you (might) have bowel cancer, your general practitioner or follow-up care specialist will refer you to an oncology team. This team may include, but is not limited to:
Medical oncologist (physician specialised in cancer)
Gastroenterologist (physician specialised in the digestive system)
Radiation oncologist (physician specialised in treating cancer with radiotherapy)
The specialist may discuss different treatment options with you.
What else can I do?
Knowing that you may be at increased risk of subsequent cancer can be difficult. Talking to friends and family can be helpful as well as specialist counselling and/or contact with support groups, such as patient organisations. For more information on taking care of your mental health, please read: Mental health problems.
To lower your risk of bowel cancer, adopting or maintaining a healthy lifestyle is extremely important. In particular, it is important to reach or maintain a healthy diet and weight, to avoid/quit smoking and drinking (too much) alcohol. Taking care of your mental health may be beneficial; even small changes to your lifestyle can have a positive impact on both your physical and mental health. For more information on taking up a healthier lifestyle, please read: Health promotion.
It is important that you are aware of the possibility of developing bowel cancer and that you know the symptoms and signs. If you have any further questions or if the information in this brochure concerns you, please contact your general practitioner or follow-up care specialist.
Where can I find more information?
You may find more information about bowel cancer online. However, it is important to be aware that this information is not always up to date or accurate.
While the PanCare PLAIN information group strives to provide accurate and complete information that is up-to-date as of the date of publication, you can check with your general practitioner or follow-up care specialist if this summary reflects the most up-to-date information available and whether it is relevant for you.
Please do not rely solely on this information. It is best to also seek the advice of a qualified medical practitioner if you have questions regarding a specific medical condition, disease, diagnosis or symptom.
No warranty or representation, expressed or implied, is made concerning the accuracy, reliability, completeness, relevance, or timeliness of this information. PanCare has produced the English version and PanCare is not responsible for the translated versions of this summary.
 van Kalsbeek, R. et al. (2021) European PANCAREFOLLOWUP recommendations for surveillance of late effects of childhood, adolescent, and Young Adult Cancer, European journal of cancer. Available at: https://www.ejcancer.com/article/S0959-8049(21)00368-3/fulltext.