COLON CANCER SCREENING

Q. An otherwise healthy 32-year-old man asks you about screening tests for colon cancer. He reports that his 2 older sisters had colon cancer at age 40 and 42, his mother had colon cancer at age 40 and endometrial cancer at age 45, and a maternal aunt had breast cancer at a young age. He notes that there was not a history of colon polyps in any family member. What should you

recommend for this patient?

a. Annual fecal occult blood testing

b. Colonoscopy now and every 1 to 2 years thereaft er

c. Colonoscopy with random biopsies to look for infl ammatory bowel disease—if not present, follow routine screening recommendations for average-risk Americans

d. Prophylactic colectomy

e. Reassurance only, since no polyps were found in family members

Ans: Answer b.

With his family history, this patient is at very high risk for colon cancer. It is unlikely that he would have a hereditary polyposis syndrome since no family member had polyps. His family history is highly concerning for hereditary nonpolyposis colorectal cancer (Lynch syndrome) because multiple fi rst-degree relatives were aff ected at an early age and because there is a family history of breast and endometrial cancer. Th is syndrome is associated with a defect in mismatch repair enzymes and leads to microsatellite instability. Screening with fecal occult blood testing is not adequately sensitive for patients at high risk—or even normal risk. Infl ammatory bowel disease does signifi cantly increase the risk of colon cancer, but nothing in the patient’s history suggests that it is present. Prophylactic colectomy would be a consideration only if testing is positive for the defective gene. (See Rex et al and Umar et al in the “Suggested

Reading” list.)