Lower GI 2017

Pelvic OARs constraints: sparing the bowel

- Practical planning approach with IMRT: «as low as possible», avoidance of peritoneal space outside PTV starting to spare from «high» doses (V40-V50) and continuing to intermediate dose (V15-V20) - Avoiding hot spots in the bowel loops overlapped with PTV - Residual GI toxicity likely to be due mainly to the irradiation of rectum and bowel within PTV, CHT (surgery…..) - Lack of dose-volume effect studies with prospective, patient-reported scoring of toxicity