Colon cancer can be hereditary

March is National Colorectal Cancer Awareness month.

Colorectal cancer is the most common type of cancer here, The Straits Times reported in May last year. About 30 new cases are diagnosed here every week.

Singaporeans, along with Americans, have one of the highest rates of colorectal cancer in the world, it was reported in March last year.

Only 10 per cent of colorectal cancer patients are under the age of 50. And only 0.5 per cent are under the age of 30.

Such cancers in patients under 50 are usually hereditary, said Dr Koh Poh Koon, a consultant colorectal Surgeon from Capstone Colorectal Surgery Centre .

He added that patients with lynch syndrome, a genetic disorder, have up to an 80 per cent risk of developing colorectal cancer.

Most patients with lynch syndrome develop the cancer in their mid-40s. They are also at a higher risk of developing other forms of cancer. The mutated genes can lead to cancers of the stomach and urinary tract.

Women with lynch syndrome can also get cancer of the ovaries or the endometrium, which is the inner membrane of the womb,said Dr Koh. Such cancers tend to be detected only in the later stages because there are usually no early-stage symptoms.

And symptoms that do show are often dismissed by younger people in the mistaken belief that these cancers affect only older people. Former cancer patient Kiat told The New Paper that he had stools which were almost black in colour.

Blood in stools It was only after he was diagnosed that he realised that this was caused by blood in his stools. Kiat said:"Mycolon was actually bleeding. But I didn't know because I didn't see actual blood in my stools."

Dr Koh said: "Often, the only clue we have that we might be at risk of such cancers is a family history involving more than three family members, over two generations. "This is especially so if one of the affected is an immediate relative or is below 50 years old."

Individuals who suspect something is wrong should strongly consider genetic screening. "It has been shown that early diagnosis and appropriate genetic screening can prevent the number of deaths caused by lynch syndrome," Dr Koh added.