Which feature best distinguishes left-sided colorectal cancer from right-sided colorectal cancer in terms of clinical presentation and surgical approach?

Explanation

## Clinical Presentation Differences Between Right and Left Colorectal Cancer ### Right-Sided Colorectal Cancer **Key Point:** Right-sided (caecal and ascending colon) cancers present insidiously with iron-deficiency anaemia and occult blood loss. - Large luminal diameter allows tumour growth without obstruction - Blood loss is chronic and often occult - Patients may present with anaemia as the first sign - Less likely to cause acute obstruction - Often diagnosed at advanced stage ### Left-Sided Colorectal Cancer **Key Point:** Left-sided (descending colon, sigmoid, and upper rectum) cancers present acutely with obstruction and altered bowel habits. - Smaller luminal diameter predisposes to obstruction - Presents with change in bowel habits, constipation, diarrhoea - Visible or frank blood in stool (haematochezia) - May present with acute colonic obstruction - Often diagnosed earlier due to alarming symptoms ### Surgical Approach Differences | Feature | Right-Sided | Left-Sided | |---------|-------------|------------| | **Resection** | Right hemicolectomy | Left hemicolectomy or sigmoid colectomy | | **Anastomosis** | Ileocolic | Colorectal or colocolonic | | **Rectal involvement** | Rare | Common (rectosigmoid) | | **APR indication** | No | Yes (if lower rectum involved) | **High-Yield:** The luminal diameter difference (5 cm right vs 2.5 cm left) explains the entire clinical dichotomy—right-sided = silent bleeding, left-sided = obstruction. **Clinical Pearl:** A patient presenting with iron-deficiency anaemia without obvious GI bleeding should raise suspicion for right-sided colorectal cancer until proven otherwise. [cite:Sabiston Textbook of Surgery Ch 52]