A Cochrane review included 6 studies with a total of 648 subjects. Studies comparing the use of temporary protective defunctioning stoma versus no stoma in patients that received low anterior resection for rectal cancer were included. Compared to controls, the use of covering stoma decreased anastomotic leakages (RR 0.33, 95% CI 0.21 to 0.53) and urgent reoperations (RR 0.23, 95% CI 0.12 to 0.42). There was no significant difference in terms of mortality (RR 0.58, 95% CI 0.14 to 2.33).
Comment: The quality of evidence is downgraded by study quality (inadequate or unclear allocation concealment and inadequate intention-to-treat adherence).