Resp - Lung Cancer

Question 1

name possible risk factors for lung cancer

Answer 1

1. smoking (active or passive)
2. increasing age (60-80 yrs)
3. occupational exposure to asbestos or silicon
4. exposure to radon or air pollution
5. family Hx
6. COPD or TB
7. chest radiotherapy

Question 2

describe the main types of lung cancer. which is most common?

Answer 2

1. Non-small cell carcinoma (85%)
   i) Squamous cell carcinoma
   
   • local spread common (often present as obstructive lesions of bronchus causing infection) but widespread metastasis relatively late
     ii) Adenocarcinomas
   • arise from mucous cells
   • invasion of pleura and mediastinal LNs common, often metastasise to brain and bone
     iii) Large cell carcinomas
   • less differentiated form of above
   • metastasise early
     iv) Carcinoid tumours
     v) Bronchoalveolar cell carcinoma
2. Small cell carcinoma (15%)
   - arise from Kultchitsky/enterochromaffin cells (endocrine cells that manufacture polypeptides and amines which act as hormones or NTs)
   - rapid growth and highly malignant, spread early and almost always inoperable at presentation

Question 3

which type of lung cancer is more common in non-smokers? in asbestos exposure?

Answer 3

adenocarcinoma

Question 4

what symptoms can be caused by a primary tumour?

Answer 4

Often asymptomatic but can have:

• persistent cough or change in nature of cough (e.g. bovine)
• dyspnoea
• haemoptysis
• weight loss, lethargy, nausea and vomiting

Question 5

what symptoms can be caused by a reginonal mets of a lung tumour?

Answer 5

• hoarseness (L RLN palsy)
• dyspnoea (anaemia, pleural or pericardial effusions)
• dysphagia (oesophageal compression)
• chest pain (parietal pleural involvement)

Question 6

which signs can be present in lung cancer?

Answer 6

Often no sign

• cervical chain/supraclavicular lymphadenopathy
• recurrent or slowly resolving pneumonia
• signs of (unilateral) pleural effusion, e.g. decreased chest expansion, stony dullness, absent breath sounds
• signs of lobar collapse, e.g. (ipsilateral) tracheal deviation, decreased airway entry
• finger clubbing
• asymmetric wheeze/stridor
• Horner’s syndrome (Pancoast tumours)
• SVC obstruction, e.g. facial swelling

Question 7

which neoplastic syndromes can be seen in lung cancer?

Answer 7

1. PTHrP release - hypercalcaemia (squamous cell carcinoma)
2. ADH release - SIADH and dilutional hyponatraemia (SCLC)
3. ACTH-like peptide release - Cushing’s syndrome (SCLC)

Question 8

which investigations might be performed on a pt with lung cancer?

Answer 8

1. bloods: FBC (?anaemia), UandE (?hypercalcaemia, hyponatraemia), LFTs, INR
2. imaging
   - CXR: may show coin lesion, hilar enlargement, consolidation, pleural effusion or bony secondaries
   - staging contrast CT: chest (TNM staging), abdo (liver and adrenal glands), brain
   - PET-CET scan: for all potentially curable pts before Tx
3. Histology
   - US-guided neck FNA: for cytology if lymphadenoapthy
   - bronchochoscopy + biopsy if endobronchial or transbronchial lesion
   - surgical biopsy: when less invasive methods unsuccessful
   - thoracoscopy: if pleural effusions or peripheral lesions
4. Other
   - genetic testing for ECFR-TK mutation (may have important implications in Tx choices for pts with NSCLC)
   - lung function tests: on all pts pre-surgery

Question 9

what is the major risk factor for malignant mesothelioma?

Answer 9

asbestos exposure (latent period of up to 50yrs)

Question 10

describe the possible presentation of malignant mesothelioma

Answer 10

Symptoms

• dyspnoea (due to pleural effusion or circumferential pleural thickening)
• chest pain (typically dull, diffuse, progressive; can occasionally be pleuritic)
• weight loss, fatigue, fever…

Signs:

• +/- palpable chest wall mass
• +/- clubbing (usually caused by underlying asbestosis)

Question 11

which investigations would be required in a pt with malignant mesothelioma

Answer 11

1. Imaging
   - CXR and CT scan: may show pleural effusion, lobulated or nodular pleural thickening, pleural mass and rib destruction, +/- features of asbestos exposure
   - MRI and PET scans: may be performed
2. Histology
   - pleural fluid: straw-coloured or blood stained. cytological analysis occasionally leads to Dx but pleural biopsy usually required
   - pleural biopsy