A 67-year-old man presents to his primary care physician with progressive fatigue and decreased exercise tolerance over the past 4 months. He reports a 10-pound unintentional weight loss and occasional constipation but denies abdominal pain. He denies chest pain or palpitations. His medical history is significant for hypertension, hyperlipidemia, and type 2 diabetes mellitus. Medications include lisinopril, atorvastatin, and metformin. Temperature is 36.8°C (98.2°F), blood pressure is 128/76 mm Hg, pulse is 88/min, and respiratory rate is 14/min. Physical examination is unremarkable. Laboratory studies demonstrate the following:
Fecal immunochemical testing is positive. Which of the following is the most appropriate next step in management?
The correct answer is:
A: Colonoscopy.
This patient has iron deficiency anemia, weight loss, and a positive stool-based colorectal cancer screening test. Colonoscopy is the appropriate next step because it allows direct visualization and biopsy of colonic lesions. A positive stool-based screening test should always be followed by diagnostic colonoscopy.
Answer choice B: CT scan of the abdomen and pelvis, is incorrect.
CT imaging may eventually be used for staging if malignancy is diagnosed. However, tissue diagnosis via colonoscopy is required first.
Answer choice C: Oral iron supplementation with repeat testing in 6 months, is incorrect.
Iron deficiency anemia in an older adult warrants evaluation for gastrointestinal blood loss and malignancy rather than empiric treatment alone.
Answer choice D: Repeat fecal immunochemical testing, is incorrect.
A positive screening test requires colonoscopy rather than repeat screening.
Answer choice E: Upper endoscopy, is incorrect.
Upper endoscopy may be appropriate in selected patients with unexplained iron deficiency anemia, but the positive colorectal screening test makes colonoscopy the highest-yield next step.
Key Learning Point
A positive stool-based colorectal cancer screening test requires follow-up colonoscopy.
