We just concluded another great traineeship week. Our trainees this month traveled from diverse points as they hailed from Saudi Arabia; Mankato, MN; Ottawa, Ontario; Durham, NC; and Seattle, WA. Our Journal club article was a study of perioperative nutrition support in malnourished surgical cancer patients.
Klek S, Sierzega M, Szybinski P, et al. Perioperative nutrition in malnourished surgical cancer patients - A prospective, randomized, controlled clinical trial. Clin Nutr. 2011 Aug 4. [Epub ahead of print]
This was a prospective randomized study of 214 malnourished patients scheduled for gastrointestinal surgery due to malignancy. All patients received parenteral nutrition (PN) for 14 days prior to surgery: post-surgery were randomized to receive either one of 4 regimens: standard enteral nutrition (EN), immunomodulating EN, standard PN or immunomodulating PN for at least 7 days. Nasojejunal tubes were used to provide EN over 20-22 hours/day. The immunomodulating EN was provided as Stresson which provides 1.25 kcals/ml, 7.1 gm arginine, 10.4 gm glutamine and 0.87 gm Omega-3 fatty acids per 1000 calories. The immunomodulating PN provided glutamine and omega-3 fatty acids at 0.1 gm/kg/day. An oral diet progression was started on the 4th postoperative day with a daily progression from water, to liquid nutrition, blenderized food, then solids on day 7.
The outcomes studied were infectious and other complications, 30-day and overall morbidity, 30-day and overall mortality, and hospital stay. Ultimately 167 patients were randomized into the 4 postoperative groups after patients were excluded due to unresectable cancer. Analysis was done on intention to treat (all 167 patients as initially randomized).
Inclusion and Exclusion Criteria were:
Patients scheduled for gastrectomy or pancreaticoduodenectomy due to malignancy determined to be at severe nutrition risk (Weight loss > 10% within 6 months, BMI < 18kg/m2, Subjective Global Assessment Grade C, albumin < 30 g/L (with no evidence of liver/kidney dysfunction), age between 18-80 years, Karnoffsky performance status > 80, with “adequate major organ function.”
Patients determined to be well-nourished, with unresectable disease, or with Karnoffsky score < 80.
Major Results reported by authors:
There were no significant differences in infections, other complications, or any other outcome between the EN and PN nutrition groups, nor were there significant differences between the standard and immunomodulating groups.
The authors concluded that: “postoperative nutritional intervention generates comparable results regardless of the route and formula used and that preoperative intervention is of the utmost importance.”
This study is remarkable for the exclusive use of malnourished patients, who are of course more likely to benefit from perioperative nutrition support. Additionally the study is randomized and analysis was conducted on all of the patients that were randomized. Unfortunately, there are a number of weaknesses to this study that limit any conclusions that can be reached.
The first thing that our group noted was the relatively modest size of the study, which was not adequately powered to detect less than a 40% difference in infectious complications, even when all enteral or all immunonutrition groups were analyzed together. The small size of each of the four subgroups (41 to 43 patients) certainly precludes analysis of any single group (such as enteral immunonutrition) alone. It is worthwhile to look back at our July 2011 article that had more than 2300 patients per group for a good idea of how many patients it takes to reliably determine if there are significant differences in infectious complications related to nutrition support.
However, we felt that one of the most important issues with this study was the use of 2 weeks of PN in all patients prior to surgery. The lack of a control group that did not receive preoperative PN makes it impossible to make any conclusions about the importance of preoperative intervention. Additionally, the use of preoperative PN raises the possibility that some of the postoperative complications of the EN groups were related to line or infectious issues that originated during the preoperative PN phase.
Other issues that we noted was that it was unclear how the actual amounts of enteral nutrition received by the patients was documented, and when patients were able to meet nutrition needs via oral intake alone.
Considering that there is now sufficient data to support an earlier introduction of food in the postoperative period, and no need for a slow diet progression, it is unclear how many (if any) of these patients would have actually required any postoperative nutrition support.
Our Take Home Message
1. The lack of a preoperative control group prevents any conclusions from being reached about the use of preoperative nutrition support.
2. The use of preoperative PN in a population with functional GI tract and small group sizes prevents any strong conclusions regarding the use or type of postoperative nutrition support.
Other News on the UVAHS GI Nutrition Website (www.ginutrition.virginia.edu):
Upcoming Webinars for Fall 2011:
· December 6: The Basics of GI Anatomy & Physiology, Part II: The Malabsorption Workup--Carol Parrish, MS, RD
Check out our new:
· “Nutrition Support Blog”
Latest Practical Gastroenterology article:
· O’Donnell, K. Severe Micronutrient Deficiencies in RYGB Patients: Rare but Potentially Devastating. Practical Gastroenterology 2011;XXXV(11):13.
Joe Krenitsky MS, RD
Carol Rees Parrish MS, RD
PS – Please feel free to forward on to friends and colleagues.