What are the symptoms of Colorectal Cancer? Read More
Will controlling one’s lifestyle reduce their risk of developing CRC? Read More
How early should one start screening? Read More

Metastatic Colorectal Cancer

What are the possible risk factors of colon and rectal cancer?

Lifestyle related factors have been strongly linked to developing colorectal cancer. But there also exists risk factors which one cannot control.

Among the known risk factors of colorectal cancer (CRC), there are those that one can have a control over (lifestyle-related) as well as those that one cannot.

The risk factors that one can control include:

I. Smoking/Drinking habits

Cigarette-smoking is an established risk factor. Ever-smokers were found to be 18% more likely to develop CRC than never smokers. Excessive alcohol consumption is another known risk. In a study, the risk of polyps increased three times for drinkers who do not smoke and 12 times for both drinkers and smokers compared with the risk of abstainers.

II. Diet

Risk of incidence of CRC has been found to be higher among those who consume a diet high in red meat and animal fat, low-fibre diets; and have a low overall intake of fruits and vegetables. On the other hand, more frequent consumption of tomatoes and fruits reduces risk substantially. Also, vegetable fibre appears to be more protective than either fruit or grain fibre.

III. Weight & physical activity

Studies show that obesity imposes a greater risk of CRC for men of all ages and for premenopausal women. Regular exercise reduces the risk. 12-14% of colon cancer cases have been estimated to be linked to lack of frequent vigorous physical activity.

The risk factors that one cannot have control over include:

I. Age & gender

CRC risk increases with age. Colorectal cancer can occur in young adults and teenagers, but risk is higher in those above 50. Also, men are at a higher risk.

II. Family history or personal history of IBD

The risk of developing CRC is higher with disease history among first degree relatives (parents, siblings). People with Inflammatory Bowel Disease (in which the colon is inflamed over a long period of time) have an increased risk of developing CRC.

III. Race & ethnicity

There exists a link between race and CRC incidence. For e.g Jews of Eastern European descent (Ashkenazi Jews) have one of the highest colorectal cancer risks among any ethnic group in the world.

IV. Being obese and overweight

There is a higher risk of incidence of CRC in persons who are obese or overweight.

V. Rare inherited conditions

Members of families with some rare inherited conditions are at a higher risk. These conditions include familial adenomatous polyposis, Gardner syndrome, Lynch syndrome, juvenile polyposis syndrome etc. A genetic testing can help analyse if one has inherited a high risk gene for CRC incidence.

What are the symptoms like?

Many of the symptoms are vague in the early stages of the disease. This is why it is important to screen regularly as recommended by your doctor. However, having one or more of the following symptoms need not mean that you necessarily have the disease. Talk to your doctor to rule out the possibilities.

  • A change in bowel habits, such as diarrhoea or constipation or change in consistency of stool, that lasts for a longer period of time
  • A feeling that bowel does not empty completely
  • Blood in stool or rectal bleeding
  • Continual pain in the abdomen with gas or cramps
  • Unexplained weight loss
  • Weakness or fatigue


AJCC: American Joint Committee on Cancer CEA: Carcinoembryonic antigen CRC: Colorectal cancer CT scan: Computed Tomography scan DNA: Deoxyribonucleic acid FOLFIRI: folinic acid, fluorouracil and irinotecan FOLFOX: Folinic acid, fluorouracil and oxaliplatin IBD: Inflammatory bowel disease NCCN: National Comprehensive Cancer Network MRI scan: Magnetic resonance imaging scan PET scan: Positron emission tomography scan TNM: Tumor, Node, Metastasis US scan: Ultrasound scan


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