The ACOSOG Z5061 trial’s primary aim was to determine whether a laparoscopic rectal cancer resection could be deemed noninferior to an open resection. The study was powered to assess oncological success based on pathologic analysis of the resected specimen. Fleshman et al need to be congratulated for having carefully conducted and honestly analyzed an important study.1 They utilized a novel composite assessment score based on both circumferential resection margin (CRM) and distal resection margin (DRM) status as well as quality of the total mesorectal excision (complete, nearly complete, incomplete) as the primary outcome measure. Noninferiority would be declared if the lower bound border of the 95% CI for the difference between the groups was greater than −6%. The 6% threshold was chosen based on clinical relevance estimation from medical oncology trials.
Roxburgh CS, Guillem JG. Outcomes of Open vs Laparoscopic Rectal Cancer Resection. JAMA Oncol. 2017;3(1):115-116. doi:10.1001/jamaoncol.2016.3205