Bowel Cancer Risk Factors

Overview

Bowel cancer, also known as colorectal cancer, is one of the most common cancers worldwide. It affects the colon or rectum and often begins as benign polyps that can turn malignant over time. By understanding the risk factors associated with bowel cancer, we can better prevent and detect it early. This article explores various risk factors, including lifestyle choices, genetic predispositions, and environmental influences.

Lifestyle risk factors

Diet

What we eat plays a big role in the development of bowel cancer. High consumption of red and processed meats has been linked to an increased risk. Processed meats like sausages, bacon, and ham contain preservatives that can be carcinogenic. Research shows that people who eat a lot of red and processed meats have a higher chance of developing bowel cancer.¹

On the other hand, a diet rich in fibre can help protect against bowel cancer. High-fibre foods include:

• Fruits
• Vegetables
• Whole grains

These foods help keep our digestive system healthy and may reduce the risk of cancer. Fibre also promotes the growth of beneficial gut bacteria that support colon health.²

Physical activity

Not getting enough exercise is another significant risk factor for bowel cancer. Regular physical activity helps maintain a healthy weight and promotes efficient digestion, reducing the time harmful substances stay in the intestines. Activities such as walking, jogging, or cycling can lower the risk of developing bowel cancer.³

Obesity

Being overweight, especially having excess fat around the abdomen, is linked to a higher risk of bowel cancer. Excess body fat can lead to inflammation and hormonal changes that may promote cancer growth. Maintaining a healthy weight through diet and exercise is crucial in reducing this risk.⁴

Alcohol and smoking

Both drinking alcohol and smoking are linked to an increased risk of bowel cancer. Alcohol can damage the lining of the bowel and liver, increasing cancer risk, especially for those who consume more than two drinks per day.⁵ Smoking introduces carcinogens into the body that can affect the colon and rectum. Long-term smokers are at a significantly higher risk of developing bowel cancer compared to non-smokers.⁶

Genetic and familial risk factors

Family history

Having a family history of bowel cancer increases an individual's risk. If a parent, sibling, or child has been diagnosed with bowel cancer, the risk is higher, especially if the relative was diagnosed before the age of 50. Genetic factors play a role in about 20-30% of bowel cancer cases.⁷

Genetic mutations

Certain genetic mutations can significantly increase the risk of bowel cancer. Notable genetic syndromes include Lynch syndrome and familial adenomatous polyposis (FAP). Lynch syndrome is caused by mutations in DNA mismatch repair genes, leading to a high risk of colorectal and other types of cancer. FAP is characterised by the development of hundreds to thousands of polyps in the colon and rectum during the teenage years, almost always leading to cancer if left untreated.⁸

Medical and environmental risk factors

Inflammatory bowel disease

Chronic inflammatory bowel diseases (IBD) like Crohn's disease and ulcerative colitis increase the risk of bowel cancer. The prolonged inflammation in the colon associated with these conditions can lead to dysplasia, a precursor to cancer. Regular monitoring and management of IBD are crucial for reducing cancer risk.⁹

Type 2 diabetes

People with type 2 diabetes are at a higher risk of developing bowel cancer. Insulin resistance and high insulin levels associated with type 2 diabetes may promote the growth of cancer cells. Although the exact mechanisms are still being studied, maintaining good glycaemic control is recommended to mitigate this risk.¹⁰

Age and gender

Age is a significant risk factor for bowel cancer. The risk increases significantly after the age of 50, with most cases occurring in people over 60. People assigned male at birth (AMAB) are generally at a higher risk than people assigned female at birth (AFAB), although the reasons for this gender difference are not entirely understood.¹¹

Radiation exposure

Previous exposure to radiation, particularly for cancer treatment in the abdominal or pelvic area, increases the risk of developing bowel cancer. The risk is higher for those who received radiation therapy during childhood.¹²

Preventive measures

Understanding these risk factors highlights the importance of preventive measures in reducing bowel cancer risk. Here are some key strategies:

Regular screening

Screening is crucial for early detection and prevention of bowel cancer. Colonoscopies can detect and remove polyps before they become cancerous. It is recommended that individuals start regular screenings at age 50, or earlier if they have a family history of bowel cancer or other risk factors.¹³

Healthy lifestyle choices

Adopting a healthy lifestyle can significantly reduce the risk of bowel cancer. This includes:

• Eating a balanced diet rich in fruits, vegetables, and whole grains
• Limiting the intake of red and processed meats
• Engaging in regular physical activity
• Maintaining a healthy weight
• Reducing alcohol consumption and quitting smoking

Managing medical conditions

Proper management of chronic conditions such as IBD and type 2 diabetes is essential. Regular check-ups and adhering to prescribed treatments can help reduce the risk of bowel cancer associated with these conditions.

Summary

Bowel cancer is influenced by various factors, ranging from lifestyle choices and genetic predispositions to medical conditions and environmental exposures. Awareness and understanding of these risk factors can guide individuals in making informed decisions about their health. By adopting preventive measures, such as regular screenings and maintaining a healthy lifestyle, the risk of developing bowel cancer can be significantly reduced.