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Lung Cancer

Epidemiology/etiology

  • Most common cause of death from malignancy in men and women
  • Cigarette smoking accounts for >90% of cases
  • Environmental – radon, asbestos, ionizing radiation
  • Host factors – pulmonary fibrosis, HIV, genetics

Classification

Small cell carcinoma (SCC)

  • Rapid growth
  • Increased likelihood of metastases
  • More responsive to chemotherapy and radiotherapy
  • Arise from neuroendocrine (APUD) cells and secrete hormones

Non-small cell carcinoma (NSCC)

  • Tend to be diagnosed in a localised form
  • Divided into 3 histological types
    • Adenocarcinoma – most common type
      • Peripheral lesions
      • Tend to invade the pleura
    • Squamous cell carcinoma
      • Central lesions – originate centrally and grow outwards toward the bronchus
      • Arise from epithelial cells, associates with production of keratin
    • Large cell carcinoma

Clinical features

  • Cough >3 weeks – due to endobronchial erosion and irritation
  • Breathlessness – due to airway occlusion
  • Haemoptysis
  • Chest pain – when tumour invades pleura
  • Wheeze
  • Hoarseness – compression of recurrent laryngeal nerve
  • Nerve compression – due to pancoast tumour in lung apex
    • Tumour invades the brachial plexus – causes C8/T1 palsy, muscle wasting and hand weakness
  • Recurrent infections

Non-metastatic extrapulmonary manifestations

  • Metabolic – weight loss, anorexia
  • Endocrine (SCC) – SIADH, gynaecomastia
  • Neurological – motor neuron disease, peripheral neuropathy
  • Vascular – anemia, DIC
  • Skeletal – clubbing

Metastatic spread

  • Spreads to mediastinal, cervical, axillary lymph nodes
  • Liver – anorexia, weight loss, nausea, right upper quadrant pain
  • Adrenal glands
  • Bone – pathological fractures
  • Brain – space occupying lesions with mass effect, ↑ICP, headache
  • Malignant pleural effusion

Investigations

  • CT – shows extent of disease
    • Include imaging of liver and adrenals
  • PET scan – to show mediastinal lymph node involvement and distant metastasis
  • Bronchoscopy – obtain biopsy
    • If carcinoma involves the first 2cm of either main bronchus then the tumour is inoperable
  • Percutaneous aspiration and biopsy
  • Endobronchial ultrasound
  • Others – FBC, LFTs

Staging – TNM

  • Used for non-small cell carcinoma (not as prognostically useful for small cell carcinoma)

Treatment

  • Surgical procedures – pneumonectomy, lobectomy, segmentectomy

NSCC

  • Stage I – lobectomy
  • Stage II – resection of primary tumour, en bloc resection of the hilar and lobar lymph nodes and mediastinal lymph node dissection
  • Stage III – generally considered inoperable
  • Adjuvant therapy
    • Chemotherapy – cisplatin, pemetrexed
    • CHART – continuous hyperfractionated accelerated radiotherapy

SCC

  • Early stage is managed with chemotherapy – cisplatin and etoposide
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