Constipation May Not Link with Colorectal Cancer

Constipation and colorectal cancer not typically associated with each other

/ Author:  / Reviewed by: Robert Carlson, M.D

(RxWiki News) Folks are considered constipated if they have three or fewer bowel movements a week. Doctors often refer these individuals to get a colonoscopy screening. But is that the right move?

A recent review of over two dozen studies showed that constipation is usually not associated with colorectal cancer.

Therefore, the authors suggested that constipated patients do not necessarily need to be referred for a colonoscopy – a procedure in which tubes are threaded through the colon to look for abnormal growths or cancer.

"Visit your doctor if you have elimination issues."

Andrew M. Power and two colleagues from the Leeds Gastroenterology Institute at St. James's University Hospital in Leeds, UK, performed a meta-analysis of 28 cross-sectional (looking at entire populations) and cohort (looking at specific groups of people) studies to see if constipation was linked to colorectal cancer.

In eight of the studies, investigators found that the number of colorectal cancer cases was lower in people who received colonoscopies because of constipation. Three studies found a trend toward lower colorectal cancer incidence.

And 17 studies found that constipation was higher in colorectal cancer patients than in people who did not have constipation.

However, the researchers concluded that these studies – which involved questionnaires – had significant design and bias issues.

“Prospective cross-sectional surveys and cohort studies demonstrate no increase in prevalence of colorectal cancer in patients or individuals with constipation. The significant association observed in case–control studies may relate to recall bias,” the authors concluded.

About 143,000 Americans will be diagnosed with colorectal cancer every year. According to the American Society of Clinical Oncologists (ASCO), colorectal cancer often has no signs.

When symptoms do occur, individuals may notice a change in bowel habits which could include diarrhea, constipation, feeling of incomplete elimination, blood in the stool, narrowing of the stool or ongoing discomfort in the abdomen (gas, bloating, cramping or feeling of fullness).

This study was published in the March issue of the American Journal of Gastroenterology. No conflicts of interest were reported.

Reviewed by: 
Review Date: 
March 27, 2013
Last Updated:
March 29, 2013