Purpose of review: To review current knowledge of the relationship between cytokines, the acute phase response (APR) and the development of cachexia.
Recent findings: Cytokines important in the initiation of the APR are also important in the genesis of cachexia. The presence of an APR or high circulating levels of pro-inflammatory cytokines are known to be related to adverse outcome in cancer patients. Studies of host cytokine genotype have demonstrated that specific host cytokine polymorphisms are associated with both the development of cachexia and reduced patient survival. The desire to be able to predict accurately survival in cancer patients has led to the description of various APR-based prognostic scoring systems.
Summary: Cachexia is an important clinical problem affecting up to two thirds of cancer patients. It results from anorexia and metabolic change and leads to loss of both adipose tissue and lean body mass, particularly in the skeletal muscle compartment. An APR is seen in half of cancer patients at presentation, and is most often determined clinically by raised plasma C-reactive protein concentrations. Adverse outcome and shortened survival have been linked to the presence of an APR. This article explores the cause and consequences of the APR in cancer cachexia.