Colon-Rectal Cancer

Keith Bradley, MD

National Alliance of Research Associates Programs

NARAP

Colon-Rectal Cancer

• 2nd leading cause of cancer deaths in U.S.

Colon-Rectal Cancer

• 2nd leading cause of cancer deaths in U.S.

• complex interactions between inherited susceptibility and environmental risk factors

Risk Factors

• Inherited

• Acquired

Inherited Risk Factors

• age > 40

• personal hx of colon-rectal cancer

• Ulcerative colitis or Crohn’s disease

• family (parents or siblings) hx of

– colon-rectal cancer or – adenomas before age 60

• Familial polyposis

Acquired Risk Factors• diet

high in low in – saturated fat - calcium– protein - folate– calories– meat (both red and white)– alcohol

• sedentary lifestyle

• smoking cigarettes

Decreased Risk

• low-fat, high-fiber diet

• nonsteroidal anti-inflammatory drugs

• post menopausal female hormone use

• polyp removal

Colon-Rectal Cancer

• 2nd leading cause of cancer deaths in U.S.

• complex interactions between inherited susceptibility and environmental risk factors

• number of new cases and deaths due to colon-rectal cancer has been decreasing

Screening

• fecal occult blood test

• flexible sigmoidoscopy

• colonoscopy

Fecal Occult Blood Test

• special cards are coated with a stool sample and returned to the physician or lab

Fecal Occult Blood Test

• special cards are coated with a stool sample and returned to the physician or lab

• fecal occult blood test

performed every 1 or 2 years

in people between the ages of 50-80 years decreases deaths due to colorectal cancer by 20 – 40%

Flexible Sigmoidoscopy• a thin, lighted tube (sigmoidoscope)

into rectum and only the descending colon• most often done

– in a doctor’s office or clinic– by a family practitioner (FP) or general internist

• patient remembers the procedure • polyps or other abnormal tissue

removed and biopsied• combined with FOBT every 3 years

Colonoscopy

• a thin, lighted tube (colonoscope)

into rectum and through the entire colon• most often done

– in a hospital or specialized setting– by a gastroenterologist (but possibly a FP)

• under conscious sedation• polyps or other abnormal tissue

removed and biopsied

Polyps

• adenomas = precursors for vast majority of colorectal cancer

• most of these adenomas are polypoid

Colon-Rectal Cancer Screening

Fewer than 50% over age 50 get screened

Colon-Rectal Cancer Screening

Fewer than 50% over age 50 get screened

In a survey,

respondents who had never had a colonoscopy

said they would rather give up three months of life

than have the test.

United States Preventive Services Task Force(USPSTF) Recommendations

• Adults, beginning at age 50 years and continuing until age 75 years

• Options– annual screening with a sensitive FOBT – flexible sigmoidoscopy every 5 years

with a mid-interval sensitive FOBT – colonoscopy every 10 years