Lung cancer Flashcards
What is bronchial carcinoma?
Carcinoma of the lung
What categories are lung cancers broadly divided into?
Based on histological appearence
- Small cell
- Non-Small cell
What are the subtypes of non-small cell carcinoma?
- Adenocarcinoma
- Squamous cell carcinoma
- Large cell carcinoma
What proportion of lung cancers are adenocarcinoma?
30-40%
What proportion of lung cancer is squamous cell carcinoma?
20-30%
What proportion of lung cancers are large cell carcinomas?
10-15%
What proportion of lung cancers are small-cell lung cancers?
10-15%
Where are squamous cell carcinomas most commonly found?
Centrally - frequently cavitate
Which type of lung cancer is most associated with smoking?
Squamous cell carcinoma
Describe the pathogenesis of squamous cell carcinoma?
Cigarette smoke irritates the respiratory tree, which over time results in the development of squamous metaplasia. Squamous cells are then subject to the effect of exposure to the carcinogens in the smoke with accumulation of genetic defects, e.g. mutation of p53 and overexpression of p63:
- Normal Pseutostratified squamous ciliated epithelium
- Bronchial Squamous Dyslpasia
- Squamous Carcinoma-in-situ (in-situ = on site/in position)
- Invasive Squamous Cell Carcinoma
What are pathological/histological features of squamous cell carcinoma?
The tumours are usually central in location and frequently cavitate. Squamous differentiation is recognised by the presence of keratin or intercellular desmosomes (prickles).
Does squamous cell lung cancer metastasize early or late?
Late
What is adenocarcinoma?
Carcinomas which are believed to develop from areas of dysplastic alveolar epithelium (atypical adenomatous hyperplasia) analogous to that encountered in other mucosal surfaces such as the colon.
At its most severe, the alveolar walls are lined by a population of atypical glandular cells which previously were regarded as being ‘bronchoalveolar carcinoma’ but are now thought of more as a form of adenocarcinoma in situ.
What proportion of lung cancers are adenocarcinomas?
30-40%
Where are adenocarcinomas more likely to occur in the lung?
peripherally
What are the histological features of adenocarcinoma of the lung?
A glandular growth pattern (acinar or papillary) or evidence of mucin production by the cells
What is the pathogenesis of adenocarcinoma of the lung?
Process of formation
- Normal lung parenchyma
- Atypical Adenomatous Hyperplasia
- Localised non-mucinous bronchioalveolar carcinoma (Adenocarcinoma-in-situ)
- Invasive Adenocarcinoma
What is the most common type of lung cancer in non-smokers?
Adenocarcinoma
What is large cell lung cancer?
Non-small cell lung cancer
These tumours are poorly differentiated and show no evidence of squamous or glandular differentiation by light microscopy
What are common sites for adenocarcinoma to metastasise to?
- Pleura
- Lymph nodes
- Brain
- Bones
- Adrenal glands
What is small cell lung carcinoma?
Previously also known as ‘oat cell’
Unlike NSCC, they metastasise very early, producing widespread bulky secondary deposits. The cells commonly express neuroendocrine markers, suggesting that this is a form of very poorly differentiated neuroendocrine carcinoma.
Why are SCLC known as neuroendocrine tumours?
They arise from neuroendocrine cells - APUD cells
Which types of lung cancer can metastasise early?
- SCLC
- LCLC
What are the histological features of SCLC?
Highly cellular tumour composed of small cells with hyperchromatic nuclei and indistinct nuceloli. The cells are delicate and the chromatin may appear smudged.
What are symptoms of lung cancer?
- Cough
- Breathlessness
- Wheeze
- Haemoptysis
- Chest pain
What are signs of lung cancer?
- Cachexia
- Anaemia
- Clubbing
- Hypertrophic pulmonary osteoarthropathy
- Supracalvicular/axillary nodes
- Consolidation
- Signs of collapse
- Pleural effusion
- Signs of metastases
- Horners syndrome
- Recurrent laryngeal nerve palsy
- Cervical radiculopathy
What is hypertrophic pulmonary osteoarthropathy?
A syndrome characterised by excessive proliferation of the skin and bone at distal parts of the extremities, which can include clubbing.
In advanced stages of HPOA, periosteal proliferation of tubular bones and synovial effusions may be present.
What are signs of lobar collapse?
- Deviated trachea
- Hyperresonance on percussion
- Reduced/no air entry
- Decreased vocal fremitus
What are signs of metastasis in lung cancer?
- Bone pain/tenderness +/- pathological fractures
- Hepatomegaly
- Confusion/fits/focal CNS signs
- Cerebellar syndrome
- Proximal myopathy
- Peripheral neuropathy
What signs might indicate that a lung cancer has metastasised to bone?
Bone tenderness +/- pathological fracture