The American Cancer Society estimated 12 million new cancer diagnoses worldwide in 2007, expecting this to more than double in the next 50 years. While international guidelines have suggested a nutritional intervention with dietary advice and/or oral nutritional supplements for malnourished cancer patients or in cancer patients who are at nutritional risk in the past, these suggestions are based largely on expert opinion as opposed to clinical trials.
In order to determine the effectiveness of oral nutritional interventions on the QOL of malnourished cancer patients and those who are at nutritional risk, Christine Baldwin, Ph.D., RD, Lecturer at the Nutritional Sciences Division at King's College in London and colleagues, electronically searched several databases for randomized control trials (RCTs) of cancer patients who were malnourished or at risk of malnutrition and receiving oral nutritional support compared to patients who received routine care. The researchers examined 13 studies for a total of 1,414 patients. They measured the mortality, weight, energy intake, and QOL of patients taking nutritional interventions compared to those on routine care.
The researchers found that nutritional intervention resulted in a wide range of effects on both weight and energy intake. The researchers also found statistically significant improvements in aspects of QOL such as emotional functioning, dyspnea, and loss of appetite. But the nutritional intervention had no influence on mortality.
"The findings suggest that oral nutritional interventions have no effect on survival and that the effect on body weight and energy intake is inconsistent but that statistically significant improvements in some aspects of QOL may be achieved," the researchers write. Despite these findings, the researchers note the limitations of the study, namely the heterogeneity of the studies—both clinically and statistically. They conclude, "It is not possible, therefore, to explain the difference found between studies, but it is likely that the factors such as site and stage of disease and indeed variations in the duration, nature, and intensity of the nutritional intervention will account for difference in effects in patients."
In an accompanying editorial, Ann O'Mara, Ph.D., RN, and Diane St. Germain, MS, RN of the Division of Cancer Prevention at the National Cancer Institute write that malnutrition can independently predict poor outcomes with cancer treatment, but that not all patients will benefit from oral nutritional support either in improved survival or in QOL. They feel that oral nutrition supplements are suggested because they are perceived to come without negative side effects. "Dietary counseling may be beneficial for patients at high risk for malnutrition and their caregivers," the editorialists write. They also feel that since the research contains limitations, it's challenging to apply the findings to practice. "Until future research provides clearer answers regarding who will benefit from nutritional interventions, the use of a comprehensive assessment, published nutritional guidelines, and early interventions are essential."