Ultra-low anterior resection following neoadjuvant chemoradiation for rectal cancer: The end of the 1-cm rule?

The surgical management of rectal cancer has evolved as techniques have improved and the use of preoperative multimodality therapy has gained acceptance as the standard of care. One of the most dynamic areas regarding surgical resection of rectal cancer has been the issue of an oncologically safe distal resection margin. Despite recommendations for the minimum acceptable distal margin shrinking from 5 cm to 2 cm and now to 1 cm over the past several decades, this question remains a topic of intense debate. Such discussion centering on the impact distal margins of resection can critically affect the ability to preserve the anal sphincter complex during rectal resection for cancer. In the present era of the surgical treatment of locally advanced rectal cancers with neoadjuvant chemoradiation, the literature has supported the potential safety of a 1-cm margin for sphincter preservation without a significant risk for unresected microscopic distal intramural spread. More recently, data has emerged demonstrating no statistical difference in oncologic outcomes in terms of local recurrence or overall survival when comparing shorter distal margins to those greater than 1 cm. This review examines the data in support of the 1-cm rule and discusses its validity in light of more recent reports in the modern multidisciplinary treatment era.