Lung Cancer Flashcards
What is the epidemiology of lung cancer?
- Third commonest cancer behind breast/prostate.
- Commonest cause of death from malignancy,
- Most common tumours in lung are caused by a metastasis (commonly breast, colon, head and neck, kidney)
what are the risk factors for lung cacner?
- Smoking is the biggest risk factor.
- Environmental tobacco smoke,
- Ionising radiation,
- air pollution
- Asbestos,
- Others, eg, fibrosing conditions of the lung
What are the signs and symptoms of lung cancer?
- Cough,
- Haemoptysis,
- Shortness of breath,
- Chest pain,
- Weight loss/anorexia,
- General malaise
What are the signs and symptoms of central lung cancer vs peripheral lung cancer?
Central - Ulceration of bronchus (haemoptysis) and can cause bronchial obstruction (pneumonia, wheeze, bronchiectasis, SOB)
Peripheral - Can have few symptoms. Can have pleural involvement which can cause pain and effusions
What are the effects of a local spread of malignancy?
- If invades pleura then can cause haemorrhagic effusion.
- Invasion of hilar lymphnodes,
- Invasion of adjacent tissue (which if invades BVs then causes haemoptysis)
- Invasion of pericardium which can cause pericardial effusion
- Invasion of mediastinum which can cause SVC obstruction, RL nerve obstruction and phrenic nerve obstruction.
- Pancoast tumours
What are the effects of SVC obstruction?
Facial oedema, headaches and a raised JVP
What are the effects of a phrenic nerve paralysis?
Raised right hemi diaphragm
What can occur due to recurrent laryngeal nerve paralysis?
Hoarseness of the voice
What are the effects of an apical/pancoast tumour?
- Severe pain,
- Weakness of arm/hands,
- Horner’s syndrome (ptosis, miosis and anhidrosis)
What are the routes of distant spread and the effects?
- Haematogenous (invasion of pulmonary veins which allows cancer to spread to liver, bone, brain and adrenal),
- Lymphatic spread to cervical lymph nodes.
What are the non-metastatic effects of lung cancer?
- ACTH secretion which causes adrenal hyperplasia, raised blood cortisol and Cushing’s syndrome.
- ADH secretion causing retention of water and SIADH.
- Parathyroid hormone related peptide (PYHrP) secretion which increases osteoclast activity causing hypercalcaemia.
- Encephalopathy, cerebellar degeneration, neuropathy, myopathy, Eaton Labert myasthenia-like syndrome, cancer associated retinopathy.
What is the histological classification of lung cancer?
- Small cell lung cancer (usually advanced at diagnosis and treated with chemo)
- Non-small cell lung cancer (treated surgery or radiotherapy)
- Adenocarcinoma
- Large cell carcinoma
- Others (tumours of mesenchymal tissue, salivary gland-type tumour, tumours of ectopic origin, neuroendocrine cells, lymphoma)
What are the likely tumours if central or peripheral in lung?
- Central tumours are likely to be squamous or small cell carcinomas.
- Peripheral are adenocarcinomas
Describe features of squamous cell carcinomas of the lung
- Arises centrally from major bronchi.
- Slow growing and metastasize late so good candidate for surgery.
- May undergo cavitation and block the bronchi leading to pneumonia or collapse.
- Microscopically presents as a malignant epithelial tumour with keratinization and/or intercellular bridges.
Describe features of adenocarcinomas of the lungs
- Common tumours seen in females and is seen in non smokers
- Appears microscopically as a glandular/solid/papillary or lepidic lesion. Has malignant glands seen
Describe features of small cell carcinoma of the lung
- Most aggressive form of lung cancer which metastasizes early and widely.
- Good response to chemo but most patients relapse.
- Microscopic appearence gas oval to spindle shaped cells, inconspicuous nucleoli, minimal cytoplasm and nuclear moulding (nuclei mould around each other)
Describe features of large cell carcinoma of the lung
- Usually a diagnosis of exclusion as it presents with an undifferentiated malignant epithelial tumour without cytological features of SCLC/glandular/squamous differentiation.
- Presents centrally.
What is a carcinoid tumour of the lung?
- Tumour of neuroendocrine cells which can be central or peripheral.
- Typical or atypical
What is the pathogenesis of lung cancer?
- Multi-step process where there is chronic irritation/stimulation of cells by carcinogens. This causes an increases in cell turnover. This causes progressive accumulation of genetic abnormalities.
What are some of the common genetic mutations seen in lung cancer?
Non-squamous NSCLC - EGFR mutations which may respond to tyrosine kinase inhibitors. ALK mutations. KRAS mutations which respond to sotorsib and BRAF mutations.
For all NSCLC - PD-L1 is over expressed may be treated with immunotherapy.
What is the stain to test for TB?
Ziehl-Neelsen sstain
Describe features mesothelioma
- It is a primary pleural tumour associated with asbestos.
- Long lag period
- Epithelial or sarcomatoid appearance or mixture
