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2ndoverall leading cause of cancerdeath in the United States

3rdin each sex

Approximately 6% of individuals in the USwill develop a cancer of the colon or

rectum within their lifetime

944,717 incident cases worldwide in 2000

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Incidence rates for colorectal cancerdiffer by sub-sites

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Vast majority of colorectal cancers are

adenocarcinomas, which are preceded by

adenomas or adenomatous polyps in most

cases Only around 10% of

adenomas will

develop into

cancers, a process

that takes at least

10 years

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147,500 colorectal cancer cases in 2003

105,500 colon

42,00 rectum

57,100 deaths from colorectal cancer

Slight decreases in mortality rates since1973 in both sexes

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Overall 5 year survival rate is 61.9%

Differs by race, age, and distribution ofdisease

Survival rates are lower among thanblacks than whites

52.8% vs. 62.6%

Survival rates are highest for localizedcancers

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Incidence rates start to increase after age 35

with a rapid increase after age 50, when

more than 90% of colorectal cancers develop

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Overall age-standardized incidencerates were 65.1 per 100,000 for men and

47.6 per 100,000 for women Male-female ratio=1.37

Mortality rates were also higher in menthan women

25.4 versus 18.0 per 100,000

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Race and Ethnicity

Higher rates and mortalities among blacks

than whites

Socioeconomic status

Possible association between low SES and

colorectal cancer mortality

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Fruit, Vegetables, and Fiber

Majority of case-control studies have shownan association between higher intake ofvegetables and lower cancer risk

Recent large cohort studies have shownweak or non-existent association betweenfiber and colon cancer risk

Folate

Higher intake of folate has been relativelyconsistently associated with lower colon

cancer risk

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Calcium

Avoidance of low intakes of calcium may

minimize risk of colon cancer

Fat, Carbohydrates, and Proteins

Excess energy intake leading to obesity

increases the risk of colon cancer

Possible association of red meat withincreased risk

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Higher BMI is associated with anincreased risk of colon cancer

Approximately twofold higher risk inindividuals who are overweight or obese

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Individuals who are more physicallyactive have a decreased risk of coloncancer

Some benefits appear to beindependent of BMI

Studies have shown dose-responserelationship between physical activity andcolorectal cancer

Highest risk observed in persons who areboth physically inactive and have high BMIs

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Alcohol

Somewhat controversial, but appears that

high alcohol intake increases risk

Tobacco

Most studies indicate excess risk in smokers

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Familial Adenomatous Polyposis (FAP)

Rare, inherited, autosomal dominantsyndrome

Causes occurrence of multiple colorectaladenomas in individuals in their 20s and 30sthat untreated, will lead to cancer

Hereditary Nonpolyposis Colorectal

Cancer (HNPCC) Autosomal dominant inherited disorder

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Family history of colorectal cancer

History of adenomatous polyps

Several low-penetrance genes

Type 2 Diabetes

Growth factors

High insulin-like growth factors

Hyperinsulinemia

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Inflammatory Bowel Disease

Gallstones and Cholecystectomy

Glucose Intolerance, Non-InsulinDependen Diabetes Mellitus

Acromegaly

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Prevention of smoking

Prevention of weight gain

Maintenance of a reasonable level ofphysical activity in adulthood

Limit red and processed meats, high-fatdairy products, highly refined grains andstarches, and sugars

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Early detection and removal ofcolorectal adenomas reduces risk ofcancer

Screening is recommended for adultsbeginning at age 50 Fecal occult blood test (FOBT) annually

Sigmoidoscopy every 5 years

Or Colonoscopy every 10 years

For high risk individuals, screening shouldbe tailored to their expected risk

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Research on modifiable hormonalpathways associated with greater risk

Role of micronutrients such as calciumand folate and other agents

Identification of genetic susceptibility

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Cancer Epidemiology, 3rded. 2006.Oxford University Press

Centers for Disease Control American Cancer Society