Lung Cancer

Question 1

Risk factors for lung cancer

Answer 1

• cigarette smoking - 90% of lung cancer, precursor lesions of meta/dysplasia
• industrial carcinogens - radioactive material, asbestos, heavy metals etc

Question 2

Classification of lung cancer

Answer 2

1. Small Cell Carcinoma (20%)
2. Non-small cell carcinoma
   - Squamous cell carcinoma
   - Adenocarcinoma
   - Others

Question 3

Routes of spread of lung cancer (4)

Answer 3

1. Local - lung, pleura, mediastinum, chest wall
2. Lymphatic - lymph nodes
3. Transcoelomic - pleural & pericardial effusions
4. Hematogenous

Question 4

Features of squamous cell carcinoma of the lung

Answer 4

• commoner in males, smokers
• hilar location, large, central necrosis & cavitation, locally invasive
• squamous differentiation, keratin pearls

Question 5

Features of adenocarcinoma of the lung

Answer 5

• equal gender incidence, not as closely linked with smoking
• peripherally located, less rapid growing than SCC, scarring, pleural involvement, glandular differentiation
• growth patterns: acinar, papillary, sold with mucin production, bronchioalveolar carcinoma (spreads along alveolar septa, looks like consolidation on XR)

Question 6

Features of small cell carcinoma of the lung

Answer 6

• high association with smoking
• usually hilar, central masses
• small neoplastic cells (oat cells, lymphocyte-like)
• scant cytoplasm, ill-defined cell borders, finely granular nuclear chromatin (salt & pepper), no glandular/squamous organization, extensive necrosis
• good response to chemo but likely to relapse, poor prognosis

Question 7

Paraneoplastic syndromes of the lung

Answer 7

• Endocrine - SIADH, ectopic ACTH secretion, hypercalcemia

- Neurological - hypertrophic pulmonary osteoarthropathy