Paraneoplastic syndromes

The paraneoplastic effects of cancer

By Sarah o'shaughnessy

What are paraneoplastic (PNS) syndromes?

• These arise from the production and release of biologically active substances
• These can affect distant organs.
• These syndromes may develop after the diagnosis of cancer OR they may be the first evidence of neoplasia - so well worth knowing about!
• Many can be life threatening but many can also be managed to help improve the quality of the patient's life.

Haematological

Hyperviscosity

Hyperhistaminaemia

Click on the icons to explore examples of paraneoplastic sydrdromes, or simply navigate through the presentation using the backwards/forwards arrows.

Endocrine-related

Immune-mediated

Pyrexia

Cachexia

Haematological PNS

• Changes in the counts of red blood cells, white blood cells and platelets can occur with neoplasia
• Anaemia and thrombocytopenia are the most common manifestations haematological PNS
• There are many different mechanisms for this...move to the next slide to find out more...

Mechanisms for paraneoplastic anaemia

• There are many different ways in which neoplasia can cause anaemia ...can you propose a few?

• Click on the question marks to find out more

Hyperviscosity syndrome

• Due to anything that makes the blood more 'sludgy'
• Examples include to increased blood cell numbers - this is known as erythrocytosis orpolycythaemia
• Or due to the excessive production gamma-globulins

Hyperhistaminaemia

• Some tumours can release histamine and vasoactive amines e.g. mast cell tumours
• This can be responsible for signs local to the tumour such as oedematous swelling, erythema and pruritus
• Or signs far away from the tumour – e.g. gastrointestinal ulcers
• Anaphylactic shock is technically possible should there be massive and sudden release of histamine from the tumour, but thankfully this is rare!

Immune-mediATED PNS

• Neoplasia can be a trigger for a wide variety of immune mediated diseases
• This is due to cross reactivity between cancer cells and healthy cells
• Examples include:
• Immune-mediated haemolytic anaemia
• Immune mediated thrombocytopenia
• Myaesthenia gravis

Endocrine related PNS

• Endocrine tumours and non-endocrine tumours can produce hormones or hormone-like substances
• The clinical signs are dependent upon the hormone that is being excessively produced...
• Move on to the next slide to explore soem examples...

Insulin

PTH

Thyroxine

Sex-hormones

Cortisol

Pyrexia

• The mechanism for pyrexia as a PNS is poorly understood - but it is thought to be due to the production of cytokines by the neoplasm
• It is important to rule out and treat other cause of pyrexia that are commonly encountered in patients with cancer such as secondary infection.

Cachexia

• The term 'cancer cachexia' describes the loss of fat and muscle in patients with cancer.
• This weight loss can be despite adequate nutritional intake.
• The underlying mechanism is uknown but is thought to be due to production of cytokines by neoplastic cells.

Take home messages

• There are many different paraneoplastic syndromes, of which, we have explored a few examples
• You will re-visit these sydromes throughout the curriculum - in syndrome specific lectures
• Keep an eye out for paraneoplastic syndromes during EMS and rotations to help you become more familiar with their presentation, investigation, and management

the end