Conflicting reports of the association between early postoperative non-steroidal anti-inflammatory drugs (NSAIDs) administration and anastomotic leak (AL) after rectal surgery have continued. The definition of AL and the exposure of NSAIDs differ from each other among studies, which may result in the different conclusions.

The aim of this retrospective study was to clarify the effect of NSAIDs on anastomotic leak from new angels.

Concerning about the side effects induced by opioids, nonsteroidal anti-inflammatory drugs (NSAIDs) have gained its popularity in ERAS protocols. NSAIDs competitively inhibits the activity of cyclooxygenases (COXs), which are involved in migration of epithelial cell and mucosal restitution, angiogenesis and collagen synthesis during healing. Conflicting reports of the association between early postoperative non-steroidal anti-inflammatory drugs (NSAIDs) administration and anastomotic leak (AL) after rectal surgery have continued.

Notably, the definition of AL and the exposure of NSAIDs (i.e. NSAIDs administration) differ from each other among the studies, which may result in the different conclusions. In concrete terms, the definition of NSAIDs administration timing varies from the first day to the first week after surgery, while the AL was also defined in multiple ways (timing varies from 14 to 90 days postoperatively, or only leaks with operative intervention included). Most previous studies suggested that early and late AL are different entities with different risk factors. These interesting evidences indicate reconsidering the effect of NSAIDs on AL is needed.

Hence, investigators defined the NSAIDs administration as at least once in the early postoperative period--the day of and the day after surgery (NSAID group), to avoid the inclusion of patients started on NSAIDs secondary to a complication. At the same time, investigators also classified AL into early AL (confirmed within 6 days) and late AL (over 6 days). Moreover, concerning the higher rate of AL in rectal surgery than colonic surgery and the trend of minimally invasive surgery, investigators performed the current study, aiming to clarify the association between early postoperative NSAIDs and anastomotic leak in rectal surgery.

Inclusion Criteria:

• Biopsy-proven adenocarcinoma of the rectum
• Age over 18 years old
• Patients underwent non-emergency minimally invasive surgery with a primary anastomosis

Exclusion Criteria:

• Incomplete medical records
• Patients with distant metastasis before surgery
• Patients with multiple primary colorectal carcinomas

patients who underwent elective rectal resection surgery