[Evaluation of safe resection margins in rectal carcinoma]

The fact that surgically well performed total mesorectal excision with negative circumferential resection margin represents one of the most important prognostic factors in colorectal carcinoma is already well known. These parameters significantly affect the incidence of local tumour recurrence as well as distant metastasis, and are thus related to the duration of patient survival. The surgeons task is to perform mesorectal excision as completely as possible, i.e., to remove the rectum with an intact cylinder of mesorectal fat. The approach of the pathologist to evaluation of total mesorectal excision specimens differs greatly from that of resection specimens from other parts of the large bowel. Besides evaluation of the usual parameters for colon cancer staging, it is essential to assess certain additional factors specific to rectal carcinomas, namely tumour distance from circumferential (radial) resection margins and the quality of the mesorectal excision. In order to accurately evaluate these parameters, knowledge of a wide range of clinical data is indispensable (results of preoperative imaging, intraoperative findings). For objective evaluation of these parameters it is necessary to introduce standardized procedures for resection specimen processing and macro and microscopic examination. This approach is based mainly on standardized macroscopic photo-documentation of the integrity of the mesorectal surface. Parallel transverse sections of the resection specimens are made with targeted tissue sampling for histological examination. It is essential to have close cooperation between surgeons and pathologists within a multidisciplinary team enabling mutual feedback.