The use of laxatives containing polyethylene glycol (PEG) may reduce the risk of colorectal tumors by 50%, according to a poster study at this year's American Association for Cancer Research Annual Meeting.
The study, the first assessment of the chemopreventive effect in humans for the compounds, was led by Denis E. Corpet, PhD, Professor at Ecole National Veterinaire in Toulouse, France, and Etienne Dorval, MD, President of Gastroenterologists of Indre-et-Loire, France.
PEG is a non-absorbed, nonmetabolized, water-soluble polymer that has been used to treat constipation in France since 1996, and was recently approved for use as a laxative in the United States and Canada. The gent is extremely potent in the chemoprevention of experimental colon carcinogenesis, according to a news release.
PEG treatment of azoxymethane-induced tumors in rats resulted in complete inhibition of invasive colon cancers. These experimental studies showed that PEG is the most potent agent against precancerous colonic lesions, or aberrant crypt foci (ACF).
“This encouraging discovery reveals the potential prevention properties of PEG-based laxatives for colorectal cancer,” Dr. Corpet said in the release. “I am confident that if PEG were taken regularly, many colorectal cancer tumors could be regressed or prevented, as we observed in this study and in studies of rats. PEG's promising chemopreventive effect offers further insight into a potential preventive agent for this major disease.
“In this study population, PEG use appears to be more protective than aspirin,” he continued. “The striking results of preclinical trials and this epidemiological study should be confirmed in a clinical trial.”
In the population-based study in France, a total of 1,165 patients (607 women, 498 men, mean age 58.3) having a routine total colonoscopy were enrolled by gastroenterologists from October 2001 to January 2002. Patients were interviewed about taking a PEG-based laxative, their risk factors for colon cancer and diet.
Of the 1,165 patients, 70% had no tumor, 28% had adenomas, and 2% had carcinomas. Of those who used a PEG-based laxative, most used Forlax, which contains the highest dose of PEG. The odds ratio of the other PEG-based laxatives were smaller than one, but none reached significance. Those who used Forlax reduced their risk of colorectal tumors by half.
“This research shows that people in France who used PEG to treat constipation were less likely to have agent tumor, which may be a reason for physicians to prescribe PEG over other laxatives for constipation,” Dr. Corpet said. “Studies of NSAIDs, calcium pills, bran supplements, and ursodeoxycholic acid to prevent polyp recurrence have also shown promising but minimal chemoprevention properties.”
The study was funded by French public agencies for research—mostly INRA and DGER—and by the French physician association GASTRO 37.
Tips for Safer Patient-Controlled Analgesia
An article in a recent issue of the Institute for Safe Medication Practices (ISMP) newsletter recommended ways to make patient-controlled analgesia (PCA) safer.
When used as intended, PCA reduces the risk of oversedation, which is an unintended consequence of the more traditional method of nurse-administered analgesia in larger, less frequent doses, the article noted.
In fact, patients often develop a synergism with the device and can quickly learn how to manage their pain while avoiding undue mental clouding.
But errors do happen, and the following factors appear to have frequently contributed to the problems, the Institute notes: (1) PCA by proxy, (2) improper patient selection, (3) inadequate monitoring, (4) inadequate patient education, (5) drug product mix-ups, (6) practice-related problems, (7) device design flaws, (8) inadequate staff training, and (9) prescription errors.