Appetite loss occurs in over half of all palliative care patients, and weight loss becomes more common in the last weeks and months of life.  Eating and food have great social, cultural and psychological significance for patients and their families, and issues relating to nutritional support are often socially and ethically complex.  The goals of nutritional support are both physical and psychosocial.  Loss of weight and loss of appetite do not always occur together. Some patients have cachexia despite maintaining a relatively normal appetite and nutritional intake. 
The cachexia anorexia syndrome is a complex metabolic syndrome of involuntary weight loss associated with cancer and some other palliative conditions including chronic heart failure and end-stage renal failure. A consensus definition of cachexia related to either cancer or chronic disease has been proposed: weight loss with or without fat loss, and at least three of the following additional criteria for diagnosis:
A systematic review of the literature on cachexia suggests that there are a range of pathways involved and that the interactions between weight loss, nutritional intake and anorexia are not straightforward or predictable. 
Assessment and management of cachexia should identify and treat according to the stage (pre-cachexia, cachexia, refractory cachexia), and seek to treat potentially reversible factors (secondary nutritional impact symptoms - S-NIS).  Nutritional assessment tools that include markers of inflammation have been investigated.  Their role in clinical practice may be to identify patients earlier in the palliative trajectory, and be incorporated into clinical practice guidelines about management of the syndrome.  Appetite is a subjective symptom. Often cachexia is poorly managed by health care professionals due to a lack of knowledge about screening and interventions and a lack of available resources, such as referral pathways. [2,8,9] There are validated assessment tools used in research and practice such as the Patient Generated Subjective Global Assessment, which has been recommended for patients with cancer cachexia,  but expert consensus does not make a recommendation about which specific tool to use.  Loss of appetite is a common symptom included in a number of severity assessment scales developed in a palliative care context, such as the Symptom Severity Scale , which is part of the PCOC dataset,  but further validation is required for these tools.
The detailed neurophysiology of appetite / anorexia is not well understood in humans. It may be different from the mechanism of cachexia / weight loss.  Genetic polymorphisms are being studied and show promise in the identification of susceptibility biomarkers. 
The metabolic profile of cancer cachexia is not the same as that of starvation, which is defined as secondary cachexia. Cancer cachexia involves inflammation, hypermetabolism, neuro-hormonal changes, and the production of proteolytic and lipolytic factors. [4,14] Raised CRP is well-established as a marker in cachexia. 
If an underlying malignancy can be effectively treated, this may reverse the cachexia anorexia syndrome. In patients who have advanced dementia, loss of appetite and decreasing oral intake may be a marker of the transition to end-stage disease, although contributing factors should be sought and addressed as appropriate. Families of patients with end-stage dementia may require increased support as they deal with this change. 
Cachexia has an impact on performance state.  Loss of weight and appetite due to cancer progression have prognostic relevance for symptom burden, performance state, survival, and the ability to tolerate palliative chemotherapy. 
Cachexia may also be a prognostic factor in non-malignant conditions. 
There is little strong evidence to support the provision of nutritional advice for weight-losing patients.  Two approaches have been identified, the first involving strategies to maximise intake, and the second focusing on allowing the patient to ‘eat what they like’. Further evidence is needed to understand whether and at what stage specific subgroups may benefit from more intensive nutritional support.
Last updated 27 August 2021