The pathological assessment of mesorectal excision: implications for further treatment and quality management

Most clinical practice guidelines today recommend total mesorectal excision (TME) for carcinoma of the middle and lower rectal thirds and partial mesorectal excision (PME) for the upper rectal third. However, these procedures may not always fulfill the oncological requirements. The pathological examination of resected rectal carcinomas should always include a visual assessment of the mesorectal excision to ensure oncological adequacy and appropriate quality. The clinical practice guideline of the German Cancer Society recommends reporting of the distal extent of mesorectal excision (total or partial without coning) and the excision in an inviolate fascial envelope.

Reporting schemas of assessment and documentation for daily use and for studies are presented.

Careful macroscopic evaluation of the resection specimen should be standardized. This may be supplemented by stain marking after postoperative filling the inferior mesenteric or superior rectal artery with ink or methylene blue solution. Photodocumentation is highly desirable. The pathological assessment of adequacy of mesorectal excision should be taken into account in selection for adjuvant radiotherapy. Objective macro- and microscopic assessment of mesorectal excision by pathologists is essential for quality management throughout patient care and in clinical trials.