Fig. 1.

Assessment of right and left sided tumours (T) and their corresponding anatomical distribution of lymph nodes. Region 1 (yellow) is +/− 5 cm oral and aboral near the tumour site and approximately 3 cm along the feeding arterial branch to the nearest arterial vessel division. Region 3 (blue) is the undivided artery from the aorta (superior mesenteric artery (SMA) or inferior mesenteric artery (IMA)) to the first artery division. Region 2 (green) is between regions 1 and 3