The Dukes staging system for colorectal carcinoma was modified by Astler and Coller (MAC). Which MAC stage corresponds to tumour penetrating through the entire bowel wall with NO lymph node involvement?
- A MAC Stage B1
- B MAC Stage C1
- C MAC Stage B2 ✓
- D MAC Stage C2
Correct answer: C. MAC Stage B2
Explanation
In the Modified Astler-Coller (MAC) classification: A = mucosa only; B1 = into muscularis propria, not through it, no nodes; B2 = through the entire bowel wall, no nodes; C1 = into but not through the bowel wall with positive nodes; C2 = through the entire bowel wall with positive nodes. MAC B2 is therefore full-thickness penetration without lymph node involvement.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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