Energy expenditure in upper gastrointestinal cancers: a scoping review.

Malnutrition is prevalent in people with upper gastrointestinal (GI) cancers, and is associated with shorter survival and poor quality of life. In order to effectively prevent or treat malnutrition, nutrition interventions must ensure appropriate energy provision to meet daily metabolic demand. In practice, energy needs of people with cancer are frequently estimated from predictive equations which are not cancer-specific, and are demonstrated to be inaccurate in this population. The purpose of this scoping review was to synthesise the existing evidence regarding energy expenditure in people with upper GI cancer. Three databases (Ovid MEDLINE, Embase via Ovid, CINAHL plus) were systematically searched to identify studies reporting on resting energy expenditure using indirect calorimetry and total energy expenditure using doubly labelled water (DLW) in adults with any stage of upper GI cancer, at any point from diagnosis. A total of 57 original research studies involving 2,125 individuals with cancer of the oesophagus, stomach, pancreas, biliary tract or liver, were eligible for inclusion. All studies used indirect calorimetry and one study used DLW to measure energy expenditure, which was reported unadjusted in 42 studies, adjusted for body weight in 32 studies, and adjusted for fat-free mass in 13 studies. Energy expenditure in upper GI cancer was compared to non-cancer controls in 19 studies, and measured vs. predicted energy expenditure was reported 31 studies. There was heterogeneity in study design and in reporting of important clinical characteristics, between studies. There was also substantial variation in energy expenditure between studies, and within and between cancer types. Given this heterogeneity and known inaccuracies of predictive equations in patients with cancer, energy expenditure should be measured in practice wherever feasible. Additional research in cohorts defined by cancer type, stage and treatment is needed to further characterise energy expenditure in upper GI cancer.