Colorectal Cancer

The objective of this article is to promote an understanding of the need for colorectal cancer (CRC) screening and prevention.

Current guidelines on screening will be presented. The awareness of risk factors will be highlighted.

1.24 million new cases of CRC were diagnosed in 2008, with 394,000 deaths from this disease. In the southern hemisphere, most cases are seen in Australia and New Zealand.

USA data predict 120,000 new cases in 2015, with 50,000 deaths. Colorectal cancer is the 3rd leading cause of cancer death in the USA.

The death rate is declining, due to more widespread screening and earlier diagnosis.
Early diagnosis results in better 5-year survival, ranging from 92% in early cancer to 11% in advanced cancer.

About 80% of colorectal cancers are sporadic, due to genetic mutations that occur in a person lifetime.

Sporadic CRCs tend to occur in older individuals, compared to inherited cancers. CRCs develop through an adenoma-cancer sequence.

The adenomas are benign premalignant lesions, which once removed, will not process to cancer.

It is this fact that makes CRC amenable to screening and prevention.
Risk factors for CRC:
Non-modifiable risk factors include

1. Age
2. Personal history of adenomatous polyps or cancer
3. Family history of colon polyps or cancer
4. Inflammatory bowel disease-ulcerative colitis and Crohn’s disease
5. Inherited genetic risk e.g. Familial adenomatous polyposis and Hereditary non-polyposis CRC or Lynch syndrome

Environmental factors:
1. Nutritional factors-eating charred red meat, a diet high in animal fat, processed meat.
2. Physical inactivity and obesity.
3. Cigarette smoking
4. Heavy alcohol consumption…