Aggressive Bowel Preps Don't Improve Long-Term Outcomes after Colon Surgery

More evidence has emerged that strong laxatives before bowel surgery don’t reduce complications after surgery, nor do they improve survival.

Traditionally, doctors prescribed laxatives to completely remove all feces from the colon before surgery, a process known as mechanical bowel preparation.

However, a study in Scotland that looked at 1,730 colon cancer surgeries performed between 2000 and 2005 found no differences in surgical complications 30 days after surgery whether patients got mechanical bowel preps or not. In addition, during 3 to 5 years of follow-up there was no difference in survival.

A research team in the West of Scotland Cancer Surveillance Unit at the University of Glasgow looked at records for 1,730 patients who had surgery for colon cancer between 2000 and 2005.  More than 8 out of 10  (84.4%) had mechanical bowel preparation before their operation.  However, after a median follow-up period of 3.5 years, an analysis showed:

  • There was no statistical difference in complications in the 30 days after surgery between the groups of patients who had mechanical bowel preparation and those who didn’t.
  • After adjustments for other factors that affect outcomes after colon surgery, mechanical bowel preparation had no impact on death from all causes.

G.A. Nicholson and his team concluded,

Neither postoperative complications nor long-term survival are improved by MBP before colonic cancer surgery.

A Cochrane Review updated in 2009 looked at 14 clinical trials including 4,921 patients.  They showed:

. . .no statistically significant differences in how well the two groups of patients (mechanical bowel preparation group and the no preparation group) did after surgery in terms of leakage at the surgical join of the bowel, mortality rates, peritonitis, need for reoperation, wound infection, and other non-abdominal complications. Consequently, there is no evidence that mechanical bowel preparation improves the outcome for patients.

Comparing 13 randomized clinical trials where 2,390 patients had some form of mechanical bowel preparation and 2,387 didn’t, the Cochrane Review found:

  • Leakage at the place where the two pieces of intestine were joined (anastomosis) was 4.2% in patients with mechanical bowel preparation (MBP) and 3.4% in those without it.
  • Surgical infections happened in 9.6% of patients with MBP and 8.3% of those who didn’t have it.

The differences weren’t statistically significant.

In addition, the Cochrane Review summarized,

Preoperative bowel preparation is time-consuming and expensive, unpleasant to the patients, and even dangerous on occasion (increased risk for inflammatory processes).


Nicholson et al., British Journal of Surgery Volume 98, Issue 6, June 2011.
Guenaga et al, Cochrane Database of Systematic Reviews, Mechanical bowel preparation for elective colorectal surgery,Issue 1, 2009.

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