A 22-year-old man presents with abdominal pain for the last 4 years. The patient reports that the pain improves with defecation. He denies nausea, vomiting, diarrhea, and weight loss. The patient has an extensive family history of colon cancer (several of whom were diagnosed before the age of 40). Colonoscopy reveals hundreds of polyps in the colon and rectum.
Which is the risk of colon cancer in this patient’s lifetime?
A. 10%
100%. This patient has familial adenomatous polyposis (FAP), an autosomal dominant disease in which patients typically have a first-degree relative with early onset colon cancer. Patients diagnosed with FAP should be offered total proctocolectomy at the time of diagnosis since the vast majority will develop colon cancer at the age of 45 and 100% will develop colon cancer in their lifetime. FAP patients should also get routine surveillance upper GI endoscopies as they are at an increased risk for gastric and duodenal carcinomas.