| The best available approaches for a low risk of | | | | only organ affected. The syndrome also carries an |
| developing Colon cancer are: o a diet high in green | | | | increased risk of cancers of the stomach, ovaries, |
| vegetables, particularly cabbage, broccoli, brussel | | | | breasts and uterus. The Colon cancers in affected |
| sprouts or cauliflower. o a diet low in red meat. In | | | | individuals tend to develop as flat lesions rather than |
| particular, avoid burnt meat, which contains | | | | as polyps. The cancers more commonly affect the |
| cancer-promoting chemicals called cyclic amines. o | | | | proximal (right sided) colon, whereas other cancers |
| keeping to a normal body weight and taking regular | | | | are more common in the distal colon (nearer the |
| exercise. o Although still controversial, it seems that | | | | rectum) or rectum. They occur at a younger age and |
| taking aspirin (eg Disprin) regularly (300mg per day or | | | | this condition should be suspected in anyone who |
| more ie one standard tablet) reduces the risk by | | | | develops Colon cancer before the age of 45. About 1 |
| about 50 per cent. However, prolonged use of aspirin | | | | per cent of Colon cancers occur in people who inherit |
| carries a risk of intestinal ulceration and bleeding, so | | | | a defect in the gene for familial polyposis coli. These |
| whether the benefits would outweigh the risks is | | | | people develop hundreds of adenomatous |
| unclear at present. Genetic factors Approximately 10 | | | | (pre-cancerous) polyps in the colon by the time they |
| per cent of Colon cancers have a strong genetic | | | | are in their teens and almost invariably develop Colon |
| factor. The commonest is hereditary non-polyposis | | | | Cancer by middle age unless the colon is removed. |
| colon cancer (HNPCC or Lynch syndrome). This | | | | Patients with ulcerative colitis or Crohn's disease of |
| condition is caused by mutation in any one of at least | | | | the colon (conditions that together affect about 1 in |
| five different genes. These genes carry the | | | | 800 of the population in Western countries) have |
| instructions for manufacturing proteins that can repair | | | | about a five-fold increased risk of Colon cancer. The |
| damaged DNA. Inheritance of this type of cancer is | | | | risk is greater if the colitis (colon inflammation) seen in |
| autosomal dominant, which means that half the | | | | both conditions affects the whole colon, and if it has |
| children of someone with HNPCC are at risk of | | | | been present for more than ten years. The risk is |
| inheriting the condition. When these genes are | | | | probably reduced by regularly taking mesalazine |
| defective, DNA repair does not take place, and | | | | (5-aminosalicylic acid), a medication that is widely used |
| damaged (mutant) DNA accumulates within cells, | | | | to reduce the risk of relapse in these diseases. |
| greatly increasing the cancer risk. The colon is not the | | | | |