Chapter 17: Gastrointestinal Disorders

COLORECTAL CANCER (CRC)

Population

• – Adults.

Recommendations

AAFP 2018, NCCN 2020

• – Modifiable Risk Factors

  • Diet:

    • Advise patients to increase consumption of fruits, non-starchy vegetables, and whole grains. Preferentially optimize nutrition from natural food sources rather than dietary supplements.

    • Cholesterol: 2-fold increased risk of CRC with increased intake.

    • Fat: 25% increased risk of serrated polyps with increased fat intake.

    • Dairy: 15% reduced risk of CRC with >8 oz of cow’s milk daily.

    • Fiber: No reduced risk of CRC or adenomatous polyps with increased fiber intake.

    • Red and processed meat: 22% increased risk of CRC with increased red and processed meat intake.

  • Lifestyle:

    • Alcohol: 8% increased risk of CRC and 24% increased risk of serrated polyps. Reducing alcohol intake does not clearly lower risk for CRC or polyps.

    • Cigarettes: 114% increased risk of high-risk adenomatous polyps and CRC in current smokers.

    • Obesity: Bariatric surgery associated with 27% reduced risk of CRC in obese individuals. Increased BMI is associated with increased mortality from CRC.

    • Occupational physical activity: 25% decreased risk of colon cancer and 12% decreased risk of rectal cancer.

    • Recreational physical activity: 20% decreased risk of colon cancer and 13% decreased risk of rectal cancer.

  • Medications:

    • Statins: Weak evidence that statin use ≥5 y is associated with decreased risk of advanced adenomatous polyps.

    • Calcium: 26% reduced risk of adenomatous polyps; 22% reduced risk of CRC in individuals taking 1400 mg daily calcium compared to 600 mg.

• – Polyp Removal

  • • Based on fair evidence, removal of adenomatous polyps reduces the risk of CRC, especially polyps >1 cm. (Ann Intern Med. 2011;154:22) (Gastrointest Endosc. 2014;80:471)

    • Based on fair evidence, complications of polyp removal include perforation of the colon and bleeding estimated at 7–9 events per 1000 procedures.

• – Interventions Without Benefit

  • • Vitamin D.

    • Folic acid.

    • Antioxidants.

USPSTF 2016

• – Aspirin: Associated with 40% decreased CRC incidence after 5–10 y of use.

  • Initiate low-dose aspirin for primary prevention of cardiovascular disease and CRC in persons aged 50–59 y with a 10-y cardiovascular event risk of ≥10%, no increased risk for bleeding, life expectancy of ≥10 y, and who are willing to take low-dose aspirin daily for 10 y. (USPSTF. Aspirin Use to Prevent Cardiovascular Disease and Colorectal Cancer. 2016.)

  • Individualize decision to initiate low-dose aspirin for persons 60–69 y of age with similar risk profile, as there is increased risk for bleeding and decreased CRC prevention benefit.

  • Insufficient evidence to initiate aspirin in persons <50 or ≥70 y of age.

Sources

• – Am Fam Physician. 2018;97(10):658-665.

• – NCCN. Colorectal Cancer Screening. 2020:1-61.

• – USPSTF. Aspirin Use to Prevent Cardiovascular Disease and Colorectal Cancer. 2016.

Population

• – Average-risk adults who have undergone baseline screening colonoscopy.