8. Respiratory Pathology Flashcards
Lung cancer as a COD
3rd most common COD
6 Causes of lung cancer
Tobacco
Asbestos exposure
Radiation (radon exposure, therapeutic radiation)
Genetic predisposition
Familial (RARE)
Other (heavy metals (chromates, arsenic, nickel))
How does smoking cause lung cancer?
Smoking damages/ destroys p53 genes which usually regulate cell cycle
Uncontrollable cell division occurs
7 Clinical features of lung cancer
Haemoptysis (coughing up blood) Cough Chest/ Shoulder pain Dyspnoea Weight loss Finger clubbing Hoarseness
What is clubbing?
Angle between nail and nail bed becomes more obtuse
What are the local effects of bronchial obstruction in Lung cancer?
Cancerous tumour pushes on bronchus/ bronchiole, no air can get in/ out, anything past obstruction collapses: causes breathlessness
Impaired drainage of bronchus: Chest infection, Pneumonia, abscess
What are the effects of invasion of local structures in Lung cancer?
Invasion of local airways and vessels: Haemoptysis, cough
Invasion around large vessels: SVC syndrome: venous congestion, head and arm oedema, ultimately circulatory collapse
Oesophagus: Dysphagia
Chest wall: Pain
Nerves: Horners syndrome
What are the effects of inflammation/ irritation/ invasion of pleura or pericardium in Lung cancer?
Pleuritis or pericarditis, with effusions
=Breathlessness
=Cardiac compromise
Name 3 features of benign tumours and give an example
Grow more slowly
Do NOT metastasis
Do NOT invade adjacent tissues
E.g. Chrondroma
What are the 3 types of non-small cell carcinoma? What percentage of lung cancers are non-small cell?
Non-Small Cell = 80%
Squamous cell carcinoma (20-40%)
Adenocarcinoma (20-40%)
Large cell carcinoma (Rare)
How does cancer arise?
Multistep accumulation of mutations resulting in:
Disordered growth
Loss of cell adhesion
Invasion of tissue by tumour
Stimulation of new vessel formation around tumours
Name 2 features of malignant tumours and give an example
Potential to metastasise
Variable clinical behaviour from relatively indolent to aggressive
Commonest are epithelial tumours: “carcinomas”
4 Characteristics of small cell carcinoma
Undifferentiated
Aggressive
Paraneoplastic syndromes
Often outgrow blood supply and become necrotic
Presentation of small cell carcinoma
Close association with smoking
Often presenting in advanced stage
Often central near bronchi
Treatment and prognosis for small cell carcinoma
Chemotherapy only option
Poor survival and prognosis
Non-small cell cancer:
3 Characteristics of Squamous cell carcinoma
Local spread, metastasize late
Traditionally central, arising from bronchial epithelium, but recently increase in peripheral SqCC
Close association with smoking
Non-small cell cancer:
Arisal of Squamous cell carcinoma
In smokers, ciliated epithelium gets irritated and changes via metaplasia into squamous epithelium
Squamous epithelium is more resistant to irritants, but has no cilia so can’t clear mucus, causes cough
What are the 5 stages in the pathway to carcinoma?
Hyperplasia Metaplasia Dysplasia Carcinoma in situ Invasive Carcinoma
Non-small cell cancer:
Adenocarcinoma: What is it and where is it?
Cancer of glandular epithelium
Tends to develop in periphery of lung around terminal airways and in interstitium
What is the precursor stage of adenocarcinoma?
Atypical adenomatous hyperplasia: proliferation of atypical cells lining the alveolar walls.
Increases in size and eventually can become invasive
Which 2 mutations lead to adenocarcinomas in smokers and non-smokers?
Smokers: K ras mutation, DNA methylation p53
Non-smokers: EGFR mutation/ amplification
Which type of lung cancer is more common in non-smokers and females?
Adenocarcinoma
Non-small cell cancer:
Adenocarcinoma: metastasis
Extrathoracic metastases common and early
Non-small cell cancer:
Adenocarcinoma cytology
Malignant cells with large nucleoli and mucin vacuoles
