Lower GI 2017

IMRT & GI toxicity

- But….negative report from a controlled trial,

WHY ?

- Constraints V35<180 cc; V40<100 cc; V45<65 cc ?...they used «peritoneal space» as «small bowel» contour - No sparing on V15-V20 ? (no !, they tested: V10-V45 not correlated..) - Little portion of bowel to be spared compared to 3DCRT ? - Major contribution from CHT and from rectum irradiation ? - It is a question of CTV/PTV volumes ? - Hot spots permitted in the PTV (V115%<5%) & no constraints on bowel >V45/Dmax

………….Good to discuss bowel constraints….come back later !