COLORECTAL CANCER – Who is at risk?

Colorectal cancer (CRC) is cancer that aects the large bowel namely the colon and rectum. It is the third most common cancer and causes major morbidities and mortalities worldwide. In Malaysia, according to the 2007 National Cancer Registry Report, CRC is the second most common cancer overall, as well as in male and females subgroups.

Early stage cancers often produce no symptom. Majority of patients who present with obvious symptoms are diagnosed in later stages of the cancer. Many symptoms of CRC are non-specific such as change in bowel habits, abdominal discomfort and unexplained weight loss or constant tiredness. Patients may notice diculty in defecation or passing red blood or dark coloured stool.

Dr Mastura MD Yusof
Dr Mastura MD Yusof

The exact cause of CRC is unknown although various risk factors are known to increase one’s risk for developing the disease. Approximately 90% are sporadic cases arising from multi interaction of factors such as aging, male gender or environmental and lifestyle factors while up to 10% are caused by unknown or known inherited changes (mutations) in genes responsible for cancer formation and progression. In general one has twice likelihood to develop CRC if there is a single-family history in a first-degree relative. Stronger risk is observed in immediate family members of a patient with history of CRC or adenomatous polyps diagnosed at age younger than 60; or a similar history in two or more first-degree relatives diagnosed at any age. The reasons for the increased risk are not clear, but it likely due to inherited genes, shared environmental factors, or some combination of these.

Aging process increases the risk for CRC with more than 70% of patients with being 65 years or older. People who suer from inflammatory bowel disease such as Ulcerative colitis and Crohn’s disease, characterized by chronic inflammation of the gut mucosa have a 4- to 20-fold relative risk of developing CRC thus they can be routinely checked by their doctors for early cancer detection.

Environmental and lifestyle risk factors related to a Westernized diet, high consumption of red meat and animal fat especially when it is highly processed or cooked in high temperature have been implicated for CRC.

Physical inactivity and excess body weight is strongly associated with CRC. Obesity, being overweight and living a sedentary lifestyle has also been linked to CRC. Obesity increases oestrogen level and decreases insulin sensitivity thus increases abdominal adiposity and risk for cancer. Diet low in fruits, vegetable and fiber and diabetes has been shown to have a weak association with risk for CRC. Smoking and alcohol are associated with CRC. The carcinogen in tobacco and Acetaldehyde from alcohol has been associated with increased risk for polyps as well as CRC.

It is important to be aware of the risks for CRC and its symptoms to allow early detection or to increase participation for screening. Survival and prognosis of patients with colon cancer depends primarily on stage at diagnosis whereby the earlier the stage at diagnosis, the higher the chance of survival.

To find out more, or to discuss your wider healthcare needs, please contact us:
T: +603 5639 1212
Subang Jaya Medical Centre
1, Jalan SS12/1A, 47500 Subang Jaya, Selangor Darul Ehsan, Malaysia.