A 55-year-old male presents with constipation, small-caliber stools, and a feeling of incomplete evacuation. What could be the potential causes, and what are the next steps?
This patient's symptoms could indicate a stricture or narrowing in the bowel, potentially due to a colon or rectal cancer, inflammatory bowel disease, or an anal fissure. He should undergo a digital rectal examination, and if warranted, a colonoscopy to further investigate the cause of his symptoms.