Introduction
Bowel cancer, also known as colorectal cancer, is one of the most common types of cancer worldwide, ranking as the third most common cancer globally. It typically starts as benign polyps in the large bowel (colon) or back passage (rectum), which can develop into malignant tumors over time. Understanding its risk factors and causes is crucial for prevention, early detection, and effective treatment.
Risk Factors
Non-Modifiable Risk Factors
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Age: The risk increases significantly with age, particularly after 50. According to the American Cancer Society, most cases are diagnosed in individuals over 50.
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Family History: Having close relatives with bowel cancer or polyps significantly increases risk.
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Genetic Conditions:
- Lynch syndrome
- Familial adenomatous polyposis (FAP)
- MUTYH-associated polyposis
- Peutz-Jeghers syndrome
- Personal Medical History: Previous colorectal polyps or cancers increase risk.
Modifiable Risk Factors
Diet and Nutrition
- High consumption of red and processed meats
- Low fiber intake
- Insufficient fruit and vegetable consumption
- Excessive alcohol consumption
"Studies have shown that eating more than 90g of red and processed meat per day can significantly increase bowel cancer risk." - World Cancer Research Fund
Lifestyle Factors
- Physical inactivity
- Obesity
- Smoking
- Excessive alcohol intake
Medical Conditions
Several medical conditions can increase bowel cancer risk:
Inflammatory Bowel Disease
- Ulcerative colitis
- Crohn's disease
Other Conditions
- Type 2 diabetes
- Previous colorectal polyps
- Previous cancer history
Causes of Bowel Cancer
Genetic Mutations
Genetic mutations can lead to abnormal cell growth in the colon and rectum. These mutations can be inherited or acquired over time. For example, mutations in the APC gene can increase the risk of developing FAP.
Environmental Factors
- Exposure to certain chemicals
- Air pollution
- Radiation exposure
- Diet and lifestyle factors
Prevention and Early Detection
Recommended Screening Tests
| Test Type | Frequency | Age to Start |
|---|---|---|
| Colonoscopy | Every 10 years | 50 |
| Sigmoidoscopy | Every 5 years | 50 |
| Stool Tests | Annually | 50 |
The Centers for Disease Control and Prevention (CDC) recommends regular screening starting at age 45 for those at average risk.
Prevention Strategies
- Maintain a healthy diet rich in fiber
- Exercise regularly
- Limit alcohol consumption
- Quit smoking
- Maintain a healthy weight
- Regular screening
- Genetic counseling for those with family history
Early Warning Signs
- Changes in bowel habits
- Blood in stool
- Unexplained weight loss
- Persistent abdominal pain
- Fatigue
For more information about bowel cancer screening and prevention, visit the American Cancer Society website or the National Cancer Institute website.