Objective measurement of the distal resection margin by MRI of the fresh and fixed specimen after partial mesorectal excision for rectal cancer: 5 cm is not just 5 cm and depends on when measured.

Background: Most studies have directly established the optimal perioperative in situ clearance margin in surgery for rectal cancer from the histologically observed extent of distal spread, neglecting the tissue variability that occurs after resection and fixation of the rectal specimen.

Purpose: To measure the length of the distal resection margin in the fresh and fixed specimen following partial mesorectal excision for rectal cancer using magnetic resonance imaging (MRI) to document tissue shrinkage after surgical removal and fixation.

Material And Methods: The length of the distal resection margin was measured by MRI of the fresh and fixed specimen and at histopathological examination of the fixed specimen in 10 patients who underwent surgery for upper rectal cancer.