Lung cancer Flashcards
Who gets lung cancer?
- 2.7:1 M:F ratio
* Average diagnosis at 60yo
What are the risk factors of lung cancer?
- Tobacco smoking; >40 cigarettes/day for several years: 20x risk
- Occupational hazards; asbestos, crystalline silica, radon
- Scarring; Hx of TB etc
- Molecular genetics
What are the (4) types of bronchogenic carcinoma?
- Small cell carcinoma
Non-small cell carcinoma:
- Squamous cell carcinoma
- Adenocarcinoma
- Large cell carcinoma
Describe small cell carcinoma (correlation with smoking, location, histology, metastasis)
- strong association with smoking
- central location of lungs
- Oat cell, neuroendocrine (histologically)
- Metastasis: Disseminated at presentation. Origin in endobronchial cells
- Tumour grows rapidly & has quick diagnosis.
- Often with local obstruction (major bronchi, SVC), regional lymph node or distant metastases at initial presentation.
- Sensitive to chemotherapy (commence ASAP) & surgery is usually NOT recommended first (generally non-curable)
- DDx: lymphoma
Describe squamous cell carcinoma (correlation with smoking, location, histology, metastasis)
- strong association with smoking
- Keratin, intracellular bridges
- Local invasoin and distant spread.
- May cavitate
- Necrosis & Haemorrhage common.
How do you classify lung cancer?
• classified as primary or secondary, benign or malignant, endobronchial or parenchymal
• Bronchogenic carcinoma (epithelial lung tumours) are the most common type of primary lung
tumour (other types make up less than 1%) - e.g. small cell lung cancer & non small cell lung cancer
• benign epithelial lung tumours can be classified as papillomas or adenomas
Describe large cell carcinoma (correlation with smoking, location, histology, metastasis)
- Strong association with smoking
- rare
- Peripheral lung
- Anaplastic, undifferentiated
- Early, distant metastasis
rare. - The entire tumour has to be examined by histology.
- Dx of exclusion.
Describe adenocarcinoma (correlation with smoking, location, histology, metastasis)
- Most common type of bronchogenic cancer.
- slightly more common in female
- WEAK association with smoking
- peripheral lung
- glandular, mucin producing histology
- early, distant metastasis
Describe adenocarcinoma in situ. When is it suspected?
- well-demarcated single or multiple nodules + pneumonic pattern (slimy mucoid, solid/consolidated) with involvement of an entire lobe.
- Suspected if there is non-resolving consolidation/pneumonia.
- Histology: non-mucinous (commonest), mucinous (25%. Worse due to mucin blocking alveoli and giving pneumonic pattern), mixed mucinous and non-mucinous (rare)
Px of lung cancer (centrally located vs. peripherally located)
- Depends on the location of tumour
- Centrally located tumours: cough, dyspnoea, wheezing, haemoptysis
- Peripherally located: pleuritic chest pain
- Tumours at apex: pancoast syndrome (e.g. Horner’s sign etc)
- Tumours secreting hormones: paraneoplastic syndromes e.g. antidiuretic hormones, ACTH etc
Ix of lung cancer (centrally located vs. peripherally located)
- Tissue sampling; cytology, histology
- Centrally located tumours: sputum, bronchial washing/brushings, endobronchial ultrasound guided transbronchial needle aspiration, bronchial biopsy
- Peripherally located tumours: FNA (CT guided, eletromagnetic navigation), pleural biopsy
- Wedge excision (more common in excising metastasis), lobectomy, pneumonectomy
Compare histology of the 4 types of bronchogenic carcinoma
○ SCC: Intercellular bridges & keratinisation: criteria for Dx, Features may not be obvious if the tumour is poorly differnetiated, Immunohistochemical stains for Dx
○ AC: glandular or papillary structures. Well differentiated.
○ Adenocarcinoma in situ: non-mucinous (commonest), mucinous (25%. Worse due to mucin blocking alveoli and giving pneumonic pattern), mixed mucinous and non-mucinous (rare)
○ Small cell carcinoma: neuroendocrine type architecture; nests, trabeculae, ribons, rosettes. High N/C ratio with enlarged ovoid nuclei, scanty cytoplasm, many mitoses, apoptotic bodies.
Who commonly have EGFR mutations that predispose to lung cancer?
young Asian females, non-smokers.
Cx of lung cancer
- Lipoid pneumonia (centrally locating tumours block the airways and alveoli do not get cleared) distal to obstructing tumour
- Atelectasis
- Bronchitis
- Bronchiectasis: destroyed bronchial wall & dilatation.
- Cavitation and abscess formation
- Fistula formation: into another airway or into a large blood vessel -> haemorrhage
- Pleuritis, pleural effusion
- Vascular thrombosis
- Sites of distant metastases: adrenals, liver, brain, bone.
- Primary lung cancer can also metastasise to other lobes and to the opposite side
Where does primary lung cancer commonly metastasise to?
adrenals, liver, brain, bone.
Primary lung cancer can also metastasise to other lobes and to the opposite side
