Effects of weight loss and sarcopenia on response to chemotherapy, quality of life, and survival.

It has frequently been shown that patients with cancer are one of the largest hospital patient groups with a prevalence for malnutrition. Weight loss is a frequent manifestation of malnutrition in patients with cancer. Several large-scale studies over the past 35 y have reported that involuntary weight loss affects 50% to 80% of these patients with the degree of weight loss dependent on tumor site and type and stage of disease. The aim of this review was to determine the consequences of malnutrition, weight loss, and muscle wasting in relation to chemotherapy tolerance, postoperative complications, quality of life, and survival in patients with cancer. The prognostic impact of weight loss on overall survival has long been recognised with recent data suggesting losses as little as 2.4% predicts survival independent of disease, site, stage or performance score. Recently the use of gold-standard methods of body composition assessment, including computed tomography, have led to an increased understanding of the importance of muscle abnormalities, such as low muscle mass (sarcopenia), and more recently low muscle attenuation, as important prognostic indicators of unfavourable outcomes in patients with cancer. Muscle abnormalities are highly prevalent (ranging from 10-90%, depending on cancer site and the diagnostic criteria used). Both low muscle mass and low muscle attenuation have been associated with poorer tolerance to chemotherapy; increased risk of postoperative complications; significant deterioration in a patients' performance status, and poorer psychological well-being, overall quality of life, and survival.