The role of radiotherapy in rectal cancer

Abstract

SUMMARY
Radiotherapy, and more recently radiochemotherapy, has
been extensively used together with surgery in the management
of rectal cancer. Pelvic radiotherapy can decrease local
failure rates when it is used before or after surgery in
resectable cancers, even when administered to patients who
underwent total mesorectal excision (TME) surgery. Preoperative
and postoperative adjuvant radiotherapy have
both been proved effective but there is not yet a randomised
trial proving the superiority of either of the two methods
through direct comparison. Although the survival advantage
of postoperative radiation therapy does not seem to be
great, the data suggests that there may be a greater survival
benefit with preoperative therapy. Preoperative
radio(chemo)therapy has also been increasingly used in
resectable low-lying tumours in order to facilitate a sphincter-
preserving procedure by decreasing tumour size. The
incidence of sphincter preservation varies between 23% and
70% and this conservative approach may be an alternative
to abdominoperitoneal resection, with good functional outcome,
in selected patients. In patients, with primarily unresectable
cancer, preoperative radiotherapy is usually administered
to cause tumour regression and allow radical
surgery. Intraoperative radiation therapy (IORT) and the
addition of systemic chemotherapy have been used in order
to improve the results of preoperative radiotherapy. In patients
with advanced unresectable rectal cancer, and also
in elderly patients, pelvic radiotherapy can provide very effective
palliation of the symptoms.