Colorectal cancer is the commonest cancer in Singapore today. About 600 new cases are diagnosed annually. The incidence rate in Singapore is similar to those seen in the developed countries. Although colorectal cancer may occur at any age, about 90% of cases occur over the age of 40 years. It is now the overall commonest cause of cancer deaths in Singapore.

WHAT IS COLORECTAL CANCER?
Colorectal cancer is a cancer that develops from the cells of the large intestine. Polyps are non-cancerous growths that may arise in the colon or rectum. With time, some of these polyps change and become cancerous. Nearly all colon and rectal cancer begin as polyps.

RISK FACTORS
Older age, male gender, smoking, a family or personal history of colorectal cancer or adenomas, inflammatory bowel disease such as Crohn’s or ulcerative colitis, and high-animal fat diets are linked with an increased risk. Non-steroidal anti-inflammatory drugs and oestrogen, diets rich in fibers, folate, calcium, vitamins D and E may reduce the risk.

CAUSES
Most colorectal cancers happen sporadically but a minority may be due to genetically inherited conditions such as Familial Adenomatous Polyposis (FAP) and Hereditary Non-polyposis Colorectal Cancers (HNPCC). These conditions may be associated with other forms of cancers as well. It is advisable to seek genetic counselling if there is a strong family history of colorectal cancers. At NCC, there is a Risk Evaluation and Prevention (REAP) Clinic for individuals to assess the risk of hereditary cancer affecting the family, to seek counseling and management.

SIGNS & SYMPTOMS
a. Bleeding from the rectum during bowel movement
b. Bowel movements containing mucus or blood
c. Diarrhoea, constipation, or feeling that bowel does not empty completely
d. Stools that are narrower than usual
e. Abdominal pain or discomfort (bloating, fullness and/or cramps)
f. Unexplained weight loss and pallor (anemia)
Cancer-related complications such as anemia, bowel obstruction and bowel perforation may also lead to symptom development. Loss of appetite and loss of weight are symptoms suggestive of advanced disease. Jaundice, cough or breathlessness raises the suspicion of distant organ involvement.

The following 2 articles will discuss issues on colorectal cancer screening, diagnosis and treatment. Do read on.