Preparation with Mechanical Bowel Cleansing or/and Oral Antibiotics or Nothing for Elective Colorectal Surgery: Two-Two-Arm Multicentre Randomised Controlled Studies (MECCLANT –C and –R Trials)

Background: Based on sound evidence, traditional mechanical bowel preparation for elective colorectal surgery has mostly been abandoned during the last two decades. However, more recent evidence from USA large databases show that mechanical bowel preparation combined with oral antibiotics, reduces significantly surgical site infections (SSI) after elective colorectal surgery. Hypothesis-Aim: We hypothesise that administration of oral antibiotics only, and not mechanical bowel preparation, is the main factor that prevents SSI. Furthermore, we consider that rectal surgery for cancer differs from colon surgery in that the former is usually associated with defunctioning stoma, which requires an empty colon. Patients-Methods: Patients to be subjected to elective colectomy for colonic neoplasms or diverticular disease will be randomised to two arms; Arm A: no bowel preparation; Arm B: mechanical bowel preparation combined with oral antibiotics (MECCLAND –C Trial). Patients scheduled for elective low anterior resection of the rectum for rectal cancer will be randomised to two arms; Arm A: mechanical bowel preparation only; Arm B: mechanical bowel preparation combined with oral antibiotics (MECCLAND –R Trial). All patients will receive intravenous antibiotics one hour prior to first surgical incision. Enemas at the day prior to surgery are optional. Participating centres are advised to implement enhanced recovery programmes in all patients. Primary End-Points: The primary end point is surgical site infection (SSI), including (i) superficial wound infection, (ii) deep wound infection, and (iii) intrabdominal infection (contaminated fluid or pus collection). Statistical Points: Considering a SSI rate of 0.12 for Arm A vs. a SSI rate of 0.06 for Arm B, a randomization rate of 1:1 and negligible drop-off rate, the sample size of either Arm of either Trial should be 356 patients.