Background: The prominent clinical feature of cachexia has traditionally been understood to be weight loss; however, in recognition of the potential for divergent behavior of muscle and adipose tissue, cachexia was recently defined as loss of muscle with or without loss of fat mass. Detailed assessments are required to verify body composition in patients with cancer cachexia.
Design: We adopted a population-based approach to study body composition in patients with cancer, with the use of diagnostic computed tomography images acquired for cancer diagnosis and follow-up. A prospective cohort of 441 patients with non-small cell lung cancer, who were referred consecutively to a regional medical oncology service in Alberta, Canada, was evaluated.
Results: At referral (median time to death: 265 d), mean body mass index (BMI; in kg/m(2)) was 24.9, with 47.4% of patients being overweight or obese. Only 7.5% overall were underweight as conventionally understood (BMI < 18.5). Analysis of computed tomography images showed extremely high heterogeneity of muscle mass within all strata of BMI. The overall prevalence of severe muscle depletion (sarcopenia) was 46.8% and was present in patients in all BMI categories. A much higher proportion of men (61%) than women (31%) met the criteria for sarcopenia.
Conclusions: Wasting of skeletal muscle is a prominent feature of patients with lung cancer, despite normal or heavy body weights. The significance of muscle wasting in normal-weight, overweight, and obese patients as a nutritional risk factor, as a prognostic factor, and as a predictor of cancer treatment toxicity is discussed in this article.