Preoperative protein may improve walking capacity before colorectal resection

Last Updated: 2015-08-03

By Joan Stephenson PhD

NEW YORK (Reuters Health) - Preparing patients for colorectal cancer resection with four weeks of individualized nutrition counseling and whey protein supplementation may improve functional walking capacity by the day of surgery more than counseling alone, according to a small, randomized pilot study.

The findings, by researchers at McGill University in Montreal, "suggest that there is a place for nutrition in preparing patients for surgery, as shown by the increase in functional walking capacity in these patients who have cancer," Chelsia Gillis, a registered dietitian, told Reuters Health by email. However, cautioned Gillis, the study's first author and now a graduate student at the University of Calgary, one "must be careful not to make clinical inferences" because of the small sample size, variability, and pilot nature of the study.

The McGill researchers found in a previous study that two months after colorectal surgery, patients participating in a four-week preoperative prehabilitation program offering exercise, counseling to reduce anxiety, and nutritional counseling plus whey protein supplementation walked significantly farther in a six-minute walk test compared with a control group receiving standard care.

Prehabilitation is the "process of enhancing an individual's functional capacity to optimize physiologic reserves before an operation to withstand the stress of surgery," the authors explained. Studies show that many patients with colorectal cancer are malnourished and experience weight loss before surgery.

The current study, published online July 21 in the Journal of the Academy of Nutrition and Dietetics, was part of an effort to look at the individual contributions of exercise, nutrition, and psychological counseling in prehabilitation.

The randomized study involved 48 patients (mean age 67.6 years and 69.1 years in the placebo and intervention groups, respectively) awaiting elective colorectal cancer resection who received individualized nutrition counseling and either supplementation with whey protein or a nonnutritive placebo for four weeks before and four weeks after surgery.

At baseline, each participant received a nutrition care plan based on his or her dietary needs as determined, in part, through analysis of patients' self-reported food records. Distance covered in a six-minute walk test at baseline, the day of surgery, and four weeks after surgery was used as a measure of functional walking capacity.

The walk test has been validated in the colorectal surgical population and is an indicator of an individual's ability to "maintain a moderate level of aerobic endurance and reflects capacity to perform activities of daily living," the authors noted.

The mean improvement in walking capacity by the day of surgery in the 22 evaluable patients receiving whey protein was 20.8 m compared with 1.2 m in the placebo group of 21 evaluable patients. They set a measure of 20 m gain as clinically meaningful.

Recovery rates by four weeks post-surgery were similar for the two groups.

The researchers noted that the study was initially designed as a randomized trial with 60 patients, but they curtailed enrollment to 48 because of a lack of personnel to carry out planned post-surgery evaluations at eight weeks. Thus the trial, with sample sizes lacking the power to show statistically significant differences, "became a pilot study to collect supportive data for a future trial with sufficient power, sample size, and staff support," they wrote.

Gillis said the researchers are beginning to collaborate with other hospitals to conduct multicenter trials on prehabilitation interventions.

"I strongly feel that prehabilitation is a laudable goal worth working for and the Gillis article is the foundation for future studies that will result in much more significant outcomes," Dr. Robert Martindale, of the Oregon Health & Science University, Portland, told Reuters Health by email. That being said, the study's flaws, such as the assumption that a 20 m gain in a six-minute walk test constitutes functional improvement or assumptions made about protein intake based on patient recall, limit its applicability, he said.

"I believe the concept of nutrition plus exercise for surgery is the future," Dr. Martindale said. "Now the studies need to be done that evaluate significantly meaningful outcome parameters and the right combination of nutrients."

In 2013, consensus recommendations from the North American Surgical Nutrition Summit suggested shifting from postoperative to preoperative preventive nutrition therapy, stressing the concept of "metabolic preparation" in all patients thought to be at nutritional risk.

The study was funded by the Canadian Foundation for Dietetic Research. The authors reported no conflicts of interest.

SOURCE: http://bit.ly/1IeF79X

J Acad Nutr Diet 2015.