What is Colorectal Cancer?
Colorectal cancer is a disease where abnormal cells in the colon or rectum grow and divide uncontrollably. These cells can form a lump or tumour, and in some cases, may spread to other parts of the body. The colon and rectum are part of the digestive system, helping to absorb nutrients and remove waste from the body.
Most colorectal cancers start as small growths called polyps on the inner lining of the bowel. While most polyps are harmless, some can turn into cancer over time. Colorectal cancer affects both men and women, typically developing after the age of 50. Like many cancers, colorectal cancer genetic screening and early detection is key, as it can greatly improve the chances of successful treatment.
Should I Consider Genetic Colorectal Cancer Testing?
If you have a family history of colorectal cancer, or related cancers such as bowel, uterine, or ovarian cancer, you may want to consider colorectal cancer genetic testing. Inherited changes (mutations) in genes such as MLH1, MSH2, MSH6, PMS2, and APC can significantly raise the risk of developing colorectal cancer. Testing can help you find out whether you carry one of these genetic changes, providing valuable information for your future health and your family's.
You might be at higher risk if you have two or more close relatives who have had colorectal cancer, if someone in your family was diagnosed at a young age (under 50), or if you have a known inherited condition like Lynch syndrome or familial adenomatous polyposis (FAP). People of Ashkenazi Jewish descent may also have a higher risk for certain gene mutations linked to colorectal cancer. Research suggests that about 5-10% of all colorectal cancers are caused by inherited genetic changes. Understanding your genetic risk can open up options for early screening, preventative care, or even risk-reducing treatments.
What are the Symptoms?
- Persistent changes in bowel habits (such as diarrhoea or constipation)
- Blood in the stool or rectal bleeding
- Abdominal pain, cramping, or bloating
- Unexplained weight loss
- Changes in bowel habits (such as constipation)
- Unexplained weight loss
- Fatigue or weakness
- Feeling that your bowel does not empty completely
These symptoms are common to many less serious conditions, but if they are new, persistent, or worsening, it’s important to speak to a doctor. Early diagnosis, especially when combined with colorectal cancer genetic screening, can make a big difference to treatment outcomes.
What are the causes?
Colorectal cancer can develop due to a range of factors, including increasing age, diet, lifestyle choices (such as smoking or lack of physical activity), and personal or family medical history. However, in many cases, there is no single known cause.
Inherited genetic mutations play a role in about 5-10% of colorectal cancers. Conditions such as Lynch syndrome (caused by mutations in mismatch repair genes like MLH1, MSH2, MSH6, or PMS2) and FAP (caused by mutations in the APC gene) greatly increase the lifetime risk of developing colorectal cancer. Genetic testing can help detect these inherited risks, allowing for earlier monitoring and preventative strategies.
What other tests are available?
Screening plays a crucial role in detecting colorectal cancer early. Common tests include the faecal immunochemical test (FIT), which checks for hidden blood in the stool, and colonoscopy, where the bowel is examined using a camera to spot and remove polyps before they turn cancerous.
If you are concerned about inherited risk, genetic testing can identify mutations linked to conditions like Lynch syndrome and FAP. Knowing your genetic status helps you and your healthcare team make informed decisions about regular screening, preventative options, and family risk management.
How is it treated?
Treatment for colorectal cancer depends on the size, location, stage, and whether the cancer has spread. Surgery is often the first step, aiming to remove the tumour. Additional treatments such as chemotherapy, radiotherapy, or targeted therapies may be used depending on the case.
For individuals with inherited genetic mutations, treatment and prevention strategies might also include regular colonoscopies, preventative surgery, or increased screening from a younger age. Your care team will work with you to find the most effective and personalised treatment plan, focusing on both successful outcomes and maintaining quality of life.
