What is bowel cancer? Bowel cancer, also known as colorectal cancer, is one of the most common cancers in Australia, with thousands of new cases diagnosed each year. It begins in the lining of the large intestine or rectum and can develop over time without noticeable symptoms.
Understanding what bowel cancer is, how bowel cancer forms, what increases the risk, and how it progresses can help with early detection and prevention.
How does bowel cancer develop?
Formation of polyps
Bowel cancer usually starts as small growths called polyps in the inner lining of the bowel. While not all polyps become cancerous, some may turn cancerous over time.
Potential cancerous changes
Certain polyps, particularly adenomatous polyps, have a higher risk of turning into cancer. Over the years, genetic mutations can cause these polyps to grow uncontrollably.
Tumour development
As cancerous cells multiply, they can form a tumour that invades surrounding tissue, affecting a patient’s normal bowel function and leading to some noticeable symptoms.
Spread beyond the bowel
If left untreated, bowel cancer can spread beyond the intestine to lymph nodes and other organs such as the liver and lungs, making treatment of the condition more challenging.
Risk factors for bowel cancer
Age
Bowel cancer is more common in people over the age of 50, with the risk increasing as individuals get older. After 50 years of age, bowel cancer screening is a must.
Genetics and family history
A family history of bowel cancer can significantly raise the likelihood of developing the disease, particularly if a close relative was diagnosed at a young age.
Lifestyle factors
A diet high in processed meats, low fibre intake, smoking, excessive alcohol consumption, and lack of exercise have all been linked to an increased risk of bowel cancer.
Existing medical conditions
Individuals with certain conditions such as inflammatory bowel disease (IBD), including Crohn’s disease, may have a higher risk of developing bowel cancer over time.
Early signs and symptoms
- Changes in bowel habits: Persistent diarrhoea, constipation, or a change in stool consistency that lasts for several weeks can be an early warning sign of bowel cancer.
- Blood in the stool): Bleeding from the rectum or blood in the stool can indicate bowel cancer, though it may also be caused by other conditions such as haemorrhoids.
- Abdominal pain or bloating: Unexplained stomach pain, bloating, or discomfort that does not go away could be a potential sign of a bowel obstruction or tumour growth.
- Unexplained weight loss: Unexplained weight loss, such as a change in diet or exercise, may sometimes indicate an underlying health issue, including bowel cancer.
Diagnosis and screening
Faecal occult blood test (FOBT)
This non-invasive test detects hidden blood in the stool, which may indicate early signs of bowel cancer. It is part of Australia’s National Bowel Cancer Screening Program.
Colonoscopy
A colonoscopy allows gastroenterologists to examine the inside of the bowel using a flexible camera. If polyps or abnormal tissue are found, they can be removed and tested.
Biopsy and imaging
A biopsy involves taking a small sample of bowel tissue for laboratory analysis. Imaging tests such as CT scans and MRIs may also be used to assess the spread of cancer.
Genetic testing and family history
For certain individuals with a strong family history of bowel cancer, genetic testing can help determine their risk level and guide personalised screening recommendations.
FAQs
While stress does not directly cause bowel cancer, chronic stress can contribute to unhealthy lifestyle habits such as poor diet, smoking, and lack of exercise, which may increase overall risk.
Although bowel cancer is more common in people over 50, cases in younger adults are rising. Lifestyle factors and genetic predisposition can contribute to early-onset bowel cancer.
There is no guaranteed way to prevent bowel cancer, but maintaining a healthy lifestyle, undergoing regular screenings, and managing known risk factors may reduce the likelihood of developing the disease.
Stay informed about bowel cancer
What is bowel cancer, and how does it develop? These are crucial questions that can help you understand and help you take steps towards early detection and better health outcomes. Being aware of risk factors, recognising early signs, and attending recommended screenings can make a significant difference in catching the disease in its earliest stages.
If you have concerns about your bowel health or a family history of bowel cancer, don’t hesitate to seek medical advice. Regular check-ups and lifestyle adjustments can support overall well-being and help reduce the risk of serious complications.
Your health is important—take the time to learn more and prioritise early detection today.
MEET DR. SUHIRDAN
Interventional Gastroenterologist and Hepatologist
Bsc (Med) | M.B.B.S. (Hons) | FRACP
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