Current Concepts on the Distal Margin of Resection of Rectal Cancer Tumors after Neoadjuvant Chemoradiation

Purpose of Review: The following review addresses concepts regarding the appropriate distal margin of resection for adenocarcinoma of the rectum in the era of preoperative chemoradiation. Recent Findings: The management of adenocarcinoma of the rectum continues to improve in all aspects of its tri-modality treatment (preoperative chemoradiation, surgery, and adjuvant therapy). The multidisciplinary approach to the management of this disease continues to evolve with a goal to provide better oncologic outcomes with less morbidity in patients affected by this disease. For locoregionally advanced disease, total mesorectal excision continues to be the standard of care for an intended cure for this cohort of patients. As we understand more regarding the oncologic benefits of preoperative chemoradiation, the appropriate distal margin of resection has also evolved to decrease morbidity and maximize postoperative quality of life. Currently, a 1.0-cm distal margin of resection is the most accepted margin after resection for adenocarcinoma of the rectum; however, several recent studies have indicated that margins of 5.0 mm or smaller are safe. A study from 2014 showed similar disease-free and overall survival rates, as well as pelvic recurrence rates, between patients with >3.0 or ≤3.0-mm distal margin of resection. Summary and Conclusion: A 1.0-cm margin is the most accepted distal margin of resection for adenocarcinoma of the rectum. Subcentimeter margins as small as 2.0–5.0 mm may be safe, as recent reports show similar rates of recurrence and survival when compared to larger margins. At this time, we require more evidence to conclude that a distal margin of resection smaller than 1.0 cm is appropriate in the surgical management of rectal cancer.