Synopsis
Detect involuntary weight and muscle loss early, distinguish cachexia from simple starvation and reversible barriers, prevent refeeding injury and align counselling, oral, enteral, parenteral, exercise and appetite treatment with cancer trajectory and patient goals.
- Cancer cachexia is a multifactorial syndrome of ongoing muscle loss, with or without fat loss, that cannot be fully reversed by conventional nutrition alone.
- A practical diagnostic threshold is weight loss above 5% over six months, or above 2% with BMI below 20 kg/m² or established sarcopenia, after clinical context is checked.
- First-line assessment records current and usual weight, percentage and rate of loss, intake, symptoms, muscle function, inflammation, cancer trajectory and treatment intent.
- Screen at diagnosis and repeatedly during treatment with a validated tool such as MUST, but use dietetic assessment rather than a score alone to prescribe care.
- Treat reversible causes first: pain, nausea, constipation, mucositis, candidiasis, depression, dysphagia, obstruction, hypercalcaemia, endocrine failure and pancreatic insufficiency.
- First-line nutrition support is individualised dietary counselling, energy- and protein-enrichment, preferred small frequent foods and oral supplements when ordinary intake remains inadequate.
- Combine nutrition with resistance and aerobic activity as tolerated because feeding without a muscle stimulus cannot fully address sarcopenia.
- Use enteral feeding when the gastrointestinal tract is functional but swallowing or intake cannot meet a realistic goal; use parenteral nutrition only when the gut is inaccessible or non-functional and expected benefit exceeds burden.
- Artificial nutrition is not routine treatment for refractory cachexia in the last phase of life and should never be framed as preventing starvation when the dying body cannot use nutrition normally.
- Before feeding, identify NICE high risk for refeeding from low BMI, major recent weight loss, little intake, low phosphate, potassium or magnesium, alcohol or relevant drug exposure.
- For high refeeding risk, start nutrition slowly, commonly no more than 10 kcal/kg/day, give thiamine 200 to 300 mg daily and replace electrolytes with close cardiac and fluid monitoring.
- In extreme risk, such as BMI below 14 kg/m² or negligible intake for more than 15 days, NICE advises about 5 kcal/kg/day with continuous rhythm monitoring.
- A short corticosteroid course can transiently improve appetite and wellbeing when prognosis is short, but muscle weakness, delirium, infection and hyperglycaemia limit duration.
- Pancreatic enzyme replacement should accompany meals and snacks in pancreatic exocrine insufficiency; increase and review delivery before assuming supplements have failed.
Key red flags
Rapid unintentional weight loss, inability to eat for more than five days or a body mass index below 18.5 requires prompt nutrition-risk and refeeding assessment.
Coughing, wet voice, recurrent chest infection or choking during intake suggests unsafe swallowing and needs speech-and-language assessment before unrestricted oral feeding.
Persistent vomiting, colic, distension or absent stool and flatus suggests obstruction; oral supplements or prokinetics may worsen risk until anatomy is clarified.
New oedema, tachycardia, arrhythmia, confusion, weakness or breathlessness after nutrition starts may be refeeding syndrome even before a laboratory value becomes profoundly abnormal.
Fever, oral ulceration, odynophagia, jaundice, severe diarrhoea or uncontrolled pain can reveal a reversible treatment or disease complication driving reduced intake.
Hyperglycaemia, hypotension, hyponatraemia or profound fatigue during immune treatment may indicate endocrine toxicity rather than cachexia alone.
A patient approaching the last days of life who no longer wants food should not be pressured or promised that artificial nutrition will reverse the dying process.
Investigation priorities
Calculate percentage and speed of unintentional loss and document actual calories, protein, fluids and barriers over time.
Management branches
Weight, muscle, intake or function declines during cancer assessment or treatment.
- Calculate loss from usual dry weight, complete validated screening and assess intake, symptoms, swallow, muscle function, inflammation, cancer stage and psychosocial access.
- Treat pain, nausea, mouth disease, constipation, obstruction, infection, endocrine and pancreatic insufficiency and refer dysphagia or high-risk nutrition promptly.
- Begin dietitian-led fortified preferred food, protein and oral supplement support with tolerable exercise and a defined weight, intake and function review date.