Summary: Carcinoma of the rectum is a heterogeneous disease. The clinical spectrum identifies a subset
of patients with locally advanced tumours that are close to or involve adjoining structures, such as the
sacrum, pelvic sidewalls, prostate or bladder. Within this group of patients categorized as ‘‘locally
advanced”, there is also variability in the extent of disease with no uniform definition of resectability.
A practice-oriented definition of a locally advanced tumour is a tumour that cannot be resected without
leaving microscopic or gross residual disease at the resection site. Since these patients do poorly with surgery alone, irradiation and chemotherapy have been added to improve the outcome. Intraoperative irradiation (IORT) is a component of local treatment intensification with favourable results in this subgroup
of patients.
International guidelines (National Comprehensive Cancer Network (NCCN) guidelines) currently recommend the use of IORT for rectal cancer resectable with very close or positive margins, especially for
T4 and recurrent cancers.
We report the ESTRO-ACROP (European Society for Radiotherapy and Oncology - Advisory Committee
on Radiation Oncology Practice) recommendations for performing IORT in primary locally advanced rectal cancer