Most cases of colorectal cancer risk factors develop from non-cancerous adenomatous polyps through a process called adenoma-carcinoma sequence, and the risk of developing colorectal cancer increases with the increase in size.
Several epidemiological studies have indicated a number of genetic and environmental factors that can predispose to colorectal cancer.
Colon Cancer Risk Factors:
- Family history: Risk of developing colorectal cancer almost doubles in an individual with a history of colorectal cancer in first-degree relatives (parents, brother, sister, or child). The risk further increases several folds for such individuals if the first-degree relative gets diagnosed with the disease at an age </=60 years.
- Genetic Cancer Predisposition Syndromes: Some inherited cancer predisposition syndromes have been reported to be associated with a high incidence rate of colorectal cancer.
Following are some examples: Lynch syndrome or hereditary non-polyposis colorectal cancer (HNPCC, generally caused by mutation in the MLH1 or MSH2 gene); Familial adenomatous polyposis (FAP, caused by mutations in the APC gene); Peutz-Jeghers syndrome (caused by mutation in LKB1); and Juvenile polyposis (caused by germline mutations in PTEN, SMAD4, BMPR1, or other genes yet to be identified).
- Personal History: Individuals with a history of colorectal cancer, adenomatous polyps, inflammatory bowel disease (ulcerative colitis or Crohn’s disease) are generally at higher risk of developing colorectal cancer.
- Age: Older age individuals are generally at increased risk of developing colorectal cancer.
- Lifestyle: Tobacco/cigarette smoking, excess alcohol consumption, and low physical activity have been reported to increase the risk of developing colorectal cancer.
- Diet: Consumption of red and processed meat, high-calorie diet, animal fat; and low intake of fruits and vegetables, fish, legumes, dietary fibers, and vitamins have been implicated to elevate the risk of colorectal cancer.
- Drugs: Use of certain drugs like aspirin, other nonsteroidal anti-inflammatory drugs (NSAID), and bisphosphonates have been reported to decrease the incidence of colorectal cancer.
Obesity, diabetes mellitus (especially type 2 diabetes), high waist girth are some other risk factors for colorectal cancer.
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To better understand colon cancer risk factors, watch the video below in which CancerBro meets Mr Collin, a colon cancer patient.
Risk factors for colon cancer
CancerBro, can you please discuss the colon cancer risk factors in detail?
Prevalence of colon cancer is more in developed countries, more so in the obese population.
And migration to the developed countries also increases the risk of the disease.
But for the past few years, the incidence of colon cancer is decreasing in USA and Canada, whereas it is increasing in China and Japan.
Moreover, it’s incidence in the population more than 50 years of age is going down, whereas, it is increasing in young population less than 50 years of age.
A diet that is rich in red meat and fats, and poor in fruits and vegetables, may also increase the risk of colon cancer.
Packaged or processed meat may also increase the risk of the disease.
Smoking is also a colon cancer risk factors for the disease, and the risk increases with the duration and intensity of smoking.
Regular and heavy alcohol consumption also increases the risk of colon cancer.
Fresh fruits and vegetables should be consumed regularly to decrease the risk of the disease.
Regular physical activity may also help in reducing the risk of the disease.
Intake of NSAIDs and calcium has also been found to reduce the risk of colon cancer.
A history of colon cancer in close relatives, especially at a young age, also increase the risk in other family members.
So these were the colon cancer risk factors.