Lung Cancer – Small Cell


Lung cancer comprises a group of malignant epithelial tumours arising from cells lining the lower respiratory tract. Lung cancer is divided into two categories: non-small cell lung cancer (NSCLC) and small cell lung cancer. SCLC accounts for more than 20% of all lung cancers.

They are responsible for paraneoplastic syndrome, as their cells contain neurosecretory granules that can release neuroendocrine hormones.

Risk factors

  • cigarette smoking
  • environmental tobacco exposure
  • chronic obstructive pulmonary disease
  • family history
  • exposure to asbestos and other carcinogens

Differential diagnosis

  • COPD
  • Sarcoidosis
  • Carcinoid tumour
  • Pneumonia
  • COVID-19


  • There are around 48,500 new lung cancer cases in the UK every year, that’s more than 130 every day (2016-2018).
  • Lung cancer is the 3rd most common cancer in the UK, accounting for 13% of all new cancer cases (2016-2018).



Approximately 45% of NSCLC are adenocarcinomas, which tend to be located more peripherally in the lung.

Clinical features

  • Persistent cough
  • Haemoptysis
  • Night sweats
  • Weight loss and anorexia
  • Breathlessness
  • Chest pain – chest wall involvement
  • Non-resolving pneumonia
  • Finger clubbing

Paraneoplastic presentations include:

Syndrome of inappropriate ADH (SIADH) caused by ectopic ADH secretion by a small cell lung cancer and presents with hyponatraemia.

Cushing’s syndrome can be caused by ectopic ACTH secretion by a small cell lung cancer.

Lambert-Eaton myasthenic syndrome presenting as weakness. It is as a result of antibodies produced by the immune system against small cell lung cancer cells. 


  • CXR
  • Contrast CT
  • Sputum cytology
  • Bronchoscopy
  • Biopsy
  • FBC, U&Es, LFTs


 Treatment regimens vary depending on the stage of cancer. 


Survival after definitive treatment and on the stage of disease and ability to undergo standard treatment.

Comparison tables