Local effects of tumours and cancer cachexia !
- Mechanism
A tumour harms by pressing, blocking, bleeding and breaking things nearby, and by making the whole body waste away.
Updated 2026-11-01
What it is
Tumours cause disease locally, through their location and growth (compression, obstruction, ulceration, bleeding, infection, fracture), and systemically, most strikingly through cachexia: progressive loss of muscle and fat with weakness and anorexia. Cachexia is driven by cytokines and tumour factors, not just by eating less, so feeding alone does not reverse it. It worsens tolerance of treatment and is a common contributor to death in advanced cancer.
Key facts
- Even small benign tumours can kill if they sit in a critical place (for example in the brain or a heart valve orifice).
- Cachexia means losing muscle as well as fat; simple starvation spares muscle at first.
- Pancreatic, gastric and lung cancers are the cancers most often associated with cachexia.
- Tumour lysis after treatment and anaemia of chronic disease are further systemic effects.
Step by step
- The tumour and the immune cells around it release cytokines: TNF, IL-1, IL-6 and interferon-γ.
- In the brain, these cytokines reduce appetite and change taste: anorexia.
- In skeletal muscle, the ubiquitin–proteasome pathway and autophagy break down proteins.
- In fat tissue, lipolysis is stimulated, partly by tumour-derived lipid-mobilizing factors.
- Unlike in starvation, energy expenditure stays high instead of adapting downward.
- The liver switches to acute-phase protein synthesis, and anaemia of inflammation adds fatigue.
Local effects of tumours, with examples
| Local effect | Example |
|---|---|
| Compression of a vital structure | Pituitary adenoma pressing on the optic chiasm; spinal cord compression by vertebral metastases |
| Obstruction of a hollow organ | Colon cancer causing bowel obstruction; pancreatic head cancer causing painless jaundice |
| Vessel compression or invasion | Superior vena cava syndrome from a mediastinal tumour |
| Nerve invasion | Apical lung tumour (Pancoast) causing Horner syndrome and arm pain |
| Ulceration and bleeding | Gastric or colorectal cancer causing iron deficiency anaemia |
| Bone destruction | Pathological fracture from metastases or myeloma |
| Hormone excess from a functioning tumour | Insulinoma causing hypoglycaemia |
| Intussusception or torsion | A polyp or tumour acting as the lead point of an intussusception |
Clinical notes
- Unintended weight loss is a classic warning sign of cancer.
- Nutritional support helps quality of life but cannot fully reverse cachexia without control of the tumour.
- Superior vena cava syndrome and spinal cord compression are oncological emergencies.
- Iron deficiency anaemia in an older adult calls for a search for gastrointestinal cancer.
Test yourself
Think of the answer, then tap the question to see it.
Which cytokines are the main drivers of cancer cachexia?
TNF, IL-1, IL-6 and interferon-γ, together with tumour-derived factors.
How does cancer cachexia differ from simple starvation?
In cachexia muscle and fat are lost together and energy expenditure stays high; in starvation the body lowers its metabolism and spares muscle at first.
Why does pancreatic head carcinoma often present with jaundice?
The tumour compresses and obstructs the common bile duct as it passes through the pancreatic head.
Which two oncological emergencies are caused by local tumour effects?
Superior vena cava syndrome and spinal cord compression (also airway or bowel obstruction).
Related
- Paraneoplastic syndromes: the table to know
- Cachexia, anorexia nervosa and bulimia
- Systemic effects of inflammation: fever, acute-phase proteins, leukocytosis, sepsis
- Pathways of spread and the usual metastatic sites
- Invasion and metastasis: the metastatic cascade, step by step
- Benign vs malignant tumours: the comparison table
Related conditions
- Pancreatic cancer
- Lung cancer
- Gastric cancer
- Colorectal cancer
- Superior vena cava syndrome
- Horner syndrome
- Anaemia of chronic disease (anaemia of inflammation)
- Iron deficiency anaemia
- Multiple myeloma
- Brain metastases
- Tumour lysis syndrome
- Malnutrition and unintentional weight loss in older adults
Elsewhere in DurgiPedia
- TNF-α
- Interleukin-6
- Acute-phase response and fever (CRP, ESR, procalcitonin)
- Warburg effect (aerobic glycolysis in cancer)
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Pancreatic Cancer (StatPearls (NCBI Bookshelf), 2024); Non–Small Cell Lung Cancer (StatPearls (NCBI Bookshelf), 2024); Gastric Cancer (StatPearls (NCBI Bookshelf), 2024).
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Representative model, for educational purposes only.