New research from Trinity College Dublin published in this month's Annals of Surgery points to a potentially significant advance in the treatment of patients undergoing major cancer surgery.
The study was carried out by the oesophageal research group at Trinity College Dublin and St James's Hospital. A randomised controlled trial showed omega-3 fatty acids given as part of an oral nutritional supplement resulted in the preservation of muscle mass in patients undergoing surgery for oesopahageal cancer, a procedure normally associated with significant weight loss and quality of life issues.
The trial was designed by Professor John V Reynolds, Professor of Surgery at Trinity College Dublin and St James's Hospital, Dublin, and Dr Aoife Ryan PhD, a research dietitian at St James's Hospital, Dublin*.
Omega 3 fats are essential fats found naturally in oily fish, with highest concentrations in salmon, herring, mackerel, and sardines. Recently food manufacturers have begun to add omega 3 to foods such as yogurt, milk, juice, eggs and infant formula in light of a body of scientific evidence which suggests that they reduce cardiovascular disease risk, blood pressure, clot formations, and certain types of fat in the blood.
Previous studies had found that nutritional supplements containing one form of omega 3 fat, eicosapentaenoic acid (EPA), significantly reduced weight loss among inoperable cancer patients. The researchers hypothesised that a nutritional supplement rich in calories and a high dose of EPA would stem the debilitating weight loss seen in patients following oesophageal surgery. The group chose to study patients undergoing surgery for oesophageal cancer as this surgery is one of the most stressful and serious operations a patient can undergo.
Professor John V Reynolds, Professor of Surgery at TCD and St James's Hospital and the lead researcher on the study said: "There are almost 450 new cases of oesophageal cancer diagnosed every year in Ireland and Ireland has one of the highest rates of oesophageal cancer in Europe. An increasing number of patients are treated with chemotherapy alone or in combination with radiation therapy before they undergo surgery. The surgery is a serious operation lasting several hours and can take weeks to recover from surgery and up to six months to recover pre-illness quality of life. Weight loss is extremely common both before and especially after this type of surgery, and any approach that can preserve weight, in particular muscle weight and strength, may represent a real advance".
In a double-blinded randomised control trial, the gold standard in medical research, patients awaiting oesophagectomy surgery were randomly assigned to treatment and control groups. While both groups received a 240ml nutritional supplement twice daily starting five days before surgery (which was identical in calories, protein, micronutrients and flavor), patients in the treatment group received an enriched formula with omega 3 (2.2 gram EPA/day). Immediately following surgery, the supplement was given through a feeding tube for 14 days while patients recovered in hospital. Once patients could resume oral feeding, they continued drinking the supplement until 21 days post surgery.
Results:
The oesophageal research group at Trinity College Dublin and St. James's Hospital found that patients given the standard feed (without omega 3) suffered clinically severe weight loss post surgery - losing an average of 4 lbs of muscle mass post surgery, where as in the omega 3 group patients maintained all aspects of their body composition
Commenting on the significance of the results, Dr Aoife Ryan said: "The results were extraordinary in the sense that no previous nutritional formulation had revealed such an outcome, with supplemented patients maintaining all aspects of their body composition in the three weeks following surgery. Patients given the standard supplement without omega 3 lost a significant amount of weight comprising 100% muscle mass. In fact 68% of patients suffered 'clinically severe' weight loss post surgery in the standard group (without omega 3) versus only 8% in the omega 3 group. The significant finding was that the patients did not lose just fat, as one would expect with weight loss, but instead they depleted their muscle stores significantly. Research has shown that a loss of 5lbs of weight produces significant effects on quality of life and a patient's ability to mobilise and perform simple activities of daily living. Losing 4 lbs of muscle is even more significant".