Moderate dose pelvic radiotherapy is associated with a 5% severe compl
ication risk related to the small bowel. Strictures and/or fistulation
can occur many years after treatment. These complications are difficu
lt to treat, and surgical treatment (excision, bypass) bears a signifi
cant morbidity risk. The risk of chronic diarrhoea or malabsorption ma
y increase to 40%, depending on the irradiated small bowel volume. Lat
e small bowel complications are generally irreversible due to vascular
aetiology. Prevention of these complications can be achieved by limit
ing the volume of small bowel treated. Consequences for radiotherapeut
ic techniques in treatment for rectal cancer are multiple beam set-up,
customised blocking based on visualisation of the small bowel in the
treatment position, and the use of a special open table-top device tha
t results in a small bowel shift from the treatment field.