A 40-year-old man comes to the office for an annual checkup. The patient has gained weight over the past year, which he attributes to a diet consisting primarily of processed food and red meat. He is otherwise asymptomatic and feels well. Medical history is significant for celiac disease, type 2 diabetes mellitus, hyperlipidemia, and a Wilms tumor treated 35 years ago with chemoradiation and surgical resection. Medications include insulin, aspirin, and simvastatin. There is no family history of colon cancer. Vital signs are normal. BMI is 48 kg/m². Examination shows acanthosis nigricans but is otherwise normal. Which aspect of this patient's history warrants colon cancer screening earlier than what is typically recommended for the general population?

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11ec25c8_d221_0933_bc81_9b8b5a271605_MD0003_00 Abdominopelvic radiation is used to treat several childhood cancers, including lymphoma, neuroblastoma, sarcoma, and Wilms tumor (nephroblastoma). However, exposure to abdominopelvic radiation is associated with a significant risk of developing colon adenocarcinoma in adulthood, with an estimated risk >4 times higher than that of the general population. The mechanism is variable and multifactorial, with contributing effects including increased mutations in colonic mucosa, chronic inflammatory changes, and underlying genetic susceptibility. For individuals with a history of abdominopelvic radiation treatment, colon cancer screening should commence at an earlier age (eg, age 30-40) than that recommended for average-risk patients (ie, age 45). Colonoscopy is preferred, although acceptable alternatives include fecal occult blood testing and fecal DNA testing. Patients with a family history of adenomatous polyps or colon cancer should also undergo screening at an earlier age. Other risk factors that warrant early screening include ulcerative colitis and certain hereditary colorectal cancer syndromes (eg, hereditary nonpolyposis colorectal cancer [Lynch syndrome], familial adenomatous polyposis). (Choice A) Although the mechanism is incompletely understood, long-term use of aspirin and nonsteroidal anti-inflammatory drugs is associated with a decreased (not increased) risk for colon cancer. (Choice B) Even though celiac disease (ie, gluten-sensitive enteropathy) predisposes patients to small bowel adenocarcinoma and lymphoma, the overall risk is low; regular screening of the small bowel for these cancers is not required. Celiac disease does not predispose patients to colorectal cancer and therefore would not influence the timing of colon cancer screening. (Choices C, E, and F) Diabetes, obesity, and daily consumption of red meat can all increase a person's chance of developing colorectal cancer, but the overall risk is small compared to that of prior abdominopelvic radiation therapy. These factors do not necessitate earlier colon cancer screening. Educational objective: Childhood cancer survivors treated with abdominopelvic radiation are at increased risk for developing colorectal adenocarcinoma. Also at higher risk are patients with inherited colon cancer syndromes and patients with a history of inflammatory bowel disease. All should start colon cancer screening at an earlier age than the general population. References: Secondary gastrointestinal cancer in childhood cancer survivors: a cohort study. (http://www.ncbi.nlm.nih.gov/pubmed/22665813) Predictors of colorectal cancer surveillance among survivors of childhood cancer treated with radiation: a report from the Childhood Cancer Survivor Study. (http://www.ncbi.nlm.nih.gov/pubmed/25649858)

A 40-Year-Old Man Comes to the Office for an Annual