Neoplasia V

Mass effect

  • Compression of adjacent structures (blood vessels, airways, bile ducts)
  • Anatomically dependent e.g. any mass effect in brain is bad
  • Can result in loss of function of organ

Energy consumption

  • Tumours are very metabolically active - divide very frequently, requiring lots of energy
    • Can lead to weight loss - cachexia
  • Tumours can also increase metabolism (mainly through TNF) which also increases weight loss

Infiltration

  • Direct invasion of other structures e.g. other organs, into brain
  • Infiltration into the nerves will result in loss of function
    • Motor - swallowing, diaphragm
    • Sensory - pain or loss of sensation
    • Autonomic functions
  • Infiltration into blood vessels - haemorrhage
  • Infiltration into bone marrow - cancer cells use up vitamins e.g. folate which are used by bone marrow to produce blood cells

Paraneoplastic syndromes

  • Tumour produces hormones which cause electrolyte disturbances
  • Osteoarthropathy - big fingers
  • Unusual neurological symptoms
  • Skin rash
  • Fever - pyrogens
    • Pyrexia of unknown origin - lots of causes but could be cancer

Immunosuppression

  • Tumours express proteins that are not normally expressed - can stimulate an immune response
    • Strong immune response = usually a good prognosis
  • Many tumours have developed mechanisms to evade the immune system
  • Cancer patients are at risk of infection – often get unusual reactions

Metastases

  • The development of secondary malignant growths at a distance from the primary site
  • Loss of function (liver, lung)
  • In bone, can cause pathological fractures
    • Calcium metabolism → increased levels of calcium → can cause arrhythmias and kidney problem