Bowel cancer is one of the most common cancers in the United Kingdom, yet it remains one of the most under-discussed. More than 42,000 people are diagnosed with it each year, and it is the second most common cause of cancer death in the UK. When detected early, however, bowel cancer is highly treatable with cure rates exceeding 90% in the earliest stage.
Awareness is not just useful in the context of bowel cancer. It is lifesaving.
This article covers what bowel cancer is, who is most at risk, what symptoms to look out for, and what treatment typically involves including the steps available to those with a family history of the condition.
Bowel cancer also referred to as colorectal cancer is cancer that develops in the large bowel (colon) or the back passage (rectum). It is distinct from small bowel cancer and anal cancer, which are separate conditions.
Most bowel cancers begin as small, non-cancerous growths on the inner lining of the bowel wall called polyps. The majority of polyps are harmless, but in some cases approximately 1 in 10 genetic changes within the polyp’s cells can lead to uncontrolled growth, eventually becoming cancerous. This process typically takes between five and ten years, which is why regular screening and early detection are so clinically significant.
Who Is Most at Risk?
Bowel cancer can affect anyone, but certain factors increase an individual’s likelihood of developing the condition. Risk factors fall into two broad categories: those that can be modified, and those that cannot.
Non-Modifiable Risk Factors
Age is the most significant non-modifiable risk factor. Almost nine in ten diagnoses occur in people over the age of 60. However, it is important to note that cases in younger adults are rising, and bowel cancer should not be dismissed in someone under 50 who presents with relevant symptoms.
Family history is another important factor. Having one close relative diagnosed with bowel cancer increases an individual’s risk. A strong family history defined as three or more close relatives diagnosed, or any close relative diagnosed before the age of 50 substantially elevates that risk and may indicate an inherited genetic condition.
Inherited genetic conditions such as Lynch syndrome and Familial Adenomatous Polyposis (FAP) are responsible for a small proportion of bowel cancers. These conditions significantly increase lifetime risk and usually warrant specialist referral and regular surveillance, including colonoscopy.
Inflammatory bowel disease (IBD) including Crohn’s disease and ulcerative colitis raises the risk of bowel cancer, particularly in those with long-standing disease. These individuals are typically offered regular screening.
Type 2 diabetes and a previous personal history of bowel polyps or bowel cancer are also recognised risk factors.
Modifiable Risk Factors
Lifestyle choices that increase bowel cancer risk include a low-fibre diet, high consumption of red or processed meat, excess alcohol intake, smoking, and carrying excess weight. Physical inactivity is also associated with increased risk. These are all areas where informed lifestyle changes can meaningfully reduce an individual’s risk over time.
One of the challenges with bowel cancer is that in its early stages, it may cause no symptoms at all. When symptoms do appear, they are often attributed to more common, less serious conditions which can contribute to delayed diagnosis.
The following symptoms warrant prompt medical attention, particularly if they persist for four weeks or more or represent a change from what is normal for you:
If the bowel becomes blocked by a tumour, symptoms may escalate to include severe cramping, bloating, inability to pass wind, and vomiting which is called bowel obstruction. This is a medical emergency and requires immediate attention, if you have these symptoms go to A&E immediately for review.
However, the presence of these symptoms should always be evaluated by a doctor and not self-managed or dismissed.
When to See a Doctor
If you have experienced any of the symptoms described in this article for four weeks or more or have a close family member diagnosed with bowel cancer, speak to your GP or contact a clinician directly.
Diagnosis
A GP will typically begin with a physical examination, which may include a rectal examination. They may then arrange a faecal immunochemical test (FIT) a simple home stool test that detects traces of blood invisible to the naked eye. A positive FIT result does not confirm cancer but indicates the need for further investigation.
Further diagnostic tests may include:
If bowel cancer is confirmed, further staging scans typically CT or MRI are used to determine whether and how far the cancer has spread. Stage at diagnosis is one of the most significant determinants of treatment options and outcome.
Treatment
Treatment for bowel cancer is managed by a multidisciplinary team (MDT) of specialists, including surgeons, oncologists, radiologists, and specialist nurses. The approach depends on the stage and location of the cancer and the individual’s overall health.
Surgery is the primary treatment for most bowel cancers. The affected section of the bowel is removed, along with nearby lymph nodes. Chemotherapy may be used before surgery to shrink a tumour, or after surgery to reduce the risk of recurrence. Radiotherapy the use of high-energy waves to destroy cancer cells.
Screening and the Importance of Family History
NHS bowel cancer screening is currently offered to adults aged 50–74 (in Scotland and Wales) and 54 – 74 (in England, with planned expansion to 50), with a home FIT kit sent every two years. Those over 75 can request a kit through their regional helpline.
Screening matters because it can identify cancer or pre-cancerous polyps before symptoms appear. Earlier detection consistently leads to better outcomes.
If you have a family history of bowel cancer, you may be eligible for additional screening or risk assessment before the standard screening age. This includes individuals with a first-degree relative diagnosed with bowel cancer, particularly if they were diagnosed before the age of 50, or if multiple relatives have been affected.
If you are concerned about any symptoms mentioned in this article, we recommend seeing a doctor for further discussion. At The Blackwell Clinic, we provide private GP appointment as well as bowel cancer risk assessment (FIT tests), this can also be accessed via your NHS GP. If you are concerned you can have a screening test, especially if you have a higher risk such as a family history of bowel cancer or your concerned. You do not need to wait for symptoms to appear or for a routine screening invitation. Speaking to a doctor early means that if additional monitoring or investigation is needed, it can be arranged promptly.
