Lung Cancer

Question 1

Epidemiology of Lung Cancer.

Answer 1

3rd commonest cancer in UK (after Breast and Prostate).

Question 2

Risk Factor of Lung Cancer.

Answer 2

Cigarette Smoking (major).

Question 3

Main Types of Lung Cancer (2).

Answer 3

1. Non-Small Cell (80%).

2. Small Cell (20%).

Question 4

Types of NSC Lung Cancers (4).

Answer 4

1. Adenocarcinoma (40%) - often in non-smokers : peripheral.
2. Squamous Cell Carcinoma (20%) : central.
3. Large Cell Carcinoma (10%) : peripheral and may secrete b-hCG.
4. Other Types (10%).

Question 5

What is a Mesothelioma?

Answer 5

Lung malignancy affecting the mesothelial cells of the pleura - poor prognosis (chemotherapy = palliative).

Question 6

Risk Factor of Mesothelioma.

Answer 6

Asbestos Inhalation (huge latency period - up to 45 years).

Question 7

What are SC Lung Cancers associated with?

Answer 7

Paraneoplastic Syndromes - SC lung cancer cells contain neurosecretory granules that can release neuroendocrine hormones.

Question 8

Pathophysiology of SC Lung Cancers.

Answer 8

Central tumours arising from APUD Kulchitsky (high content of Amine, Precursor Uptake, Decarboxylase) cells.

Question 9

Pathophysiology of SCC Lung Cancer.

Answer 9

Metaplasia - Dysplasia - Carcinoma Sequence : Columnar Epithelium becomes Squamous Epithelium by smoking.

Question 10

Clinical Features of Lung Cancer (6).

Answer 10

1. SOB & Fixed Monophonic Wheeze.
2. Persistent Cough & Haemoptysis.
3. Finger Clubbing.
4. Recurrent Pneumonia.
5. Constitutional Symptoms.
6. Lymphadenopathy (Supraclavicular).

Question 11

Extrapulmonary Manifestations of Lung Cancer (4).

Answer 11

1. Recurrent Laryngeal Nerve Palsy : Hoarse Voice (Compression of Recurrent Laryngeal Nerve).
2. Phrenic Nerve Palsy : SOB (Compression of Phrenic Nerve).
3. SVC Obstruction : Facial Swelling, Difficulty Breathing, Distended Veins in Neck + Chest (Right-Sided Compression of SVC).
4. Horner’s Syndrome : Triad of Partial Ptosis, Anhidrosis, Miosis OR Pancoast’s Syndrome (Shoulder pain radiating down ulnar arm) -(Pancoast’s Tumour (C8, T1, T2 Nerves) - Pulmonary Apex Tumour = Compression of Sympathetic Ganglion).

Question 12

Paraneoplastic Syndromes of Lung Cancer (5).

Answer 12

1. SIADH - Ectopic ADH Secretion : Hyponatraemia (SC).
2. Cushing’s Syndrome - Ectopic ACTH Secretion (SC) = Bilateral Adrenal Cortical Hyperplasia.
3. Hypercalcaemia - Ectopic PTHrp Secretion (SCC).
4. Limbic Encephalitis (Anti-Hu autoantibodies against limbic system) : Short Term Memory Impairment, Hallucinations, Confusion and Seizures.
5. Lambert-Eaton Myasthenia Syndrome (SC).
6. Hypertrophic Pulmonary Osteoarthropathy (HPOA - NSC) - proliferative periostitis at the ends of the long bones, which have an ‘onion skin’ appearance.
7. Hyperthyroidism - Ectopic TSH Secretion (SCC).
8. Gynaecomastia (Adenocarcinoma).

Question 13

Pathophysiology of Lambert-Eaton Myasthenia Syndrome.

Answer 13

Antibodies against SC cells but they also target and damage VGCCs on presynaptic terminals of motor neurones.

Question 14

Clinical Features of Lambert-Eaton Myasthenia Syndrome.

Answer 14

1. Proximal Muscle Weakness.
2. Intraocular Muscle Weakness - Diplopia.
3. Levator (Eyelid) Muscle Weakness - Ptosis.
4. Pharyngeal Muscle Weakness : Slurred Speech and Dysphagia.
5. Autonomic Dysfunction : Dry Mouth, Blurred Vision, Impotence, Dizziness.
6. Post-Tetanic Potentiation

Question 15

What is Post-Titanic Potentiation?

Answer 15

Reduced Tendon Reflexes but become normal briefly following strong muscle contraction.

Question 16

How does Cushing’s syndrome present in SC Lung Cancer?

Answer 16

Thirst + Polyuria = Atypical : HTN, Hyperglycaemia, Hypokalaemia Alkalosis and Muscle Weakness (less buffalo hump).

Question 17

How does SIADH present in Lung Cancer?

Answer 17

Cerebral Oedema due to water intoxication e.g. clumsiness, tiredness (increasing drowsiness and confusion) : low serum Sodium and osmolality due to increased water resorption.

Question 18

Investigations of Lung Cancer (4).

Answer 18

1. CXR - 1st line.
2. CT TAP - Suspicion OR Staging (Contrast-Enhanced).
3. PET-CT - Metastasis.
4. Bronchoscopy with EBUS (Endotrachial US) - Biopsy.

Question 19

CXR Findings of Lung Cancer (4).

Answer 19

1. Hilar Enlargement.
2. Peripheral Opacity - Visible Lesion in Lung Field.
3. Pleural Effusion (Unilateral).
4. Collapse.

Question 20

How do PET-CT scans work? (3)

Answer 20

1. Inject radioactive tracer (attached to glucose).
2. Use CT and y-detector to visualise how metabolically active tissues are.
3. More Metabolic Activity = ?Cancer?

Question 21

How do EBUS procedures work? (2)

Answer 21

1. Endoscopy of the Bronchi with US at end of scope.

2. Detailed assessment of tumour and US-guided biopsy.

Question 22

Referral Criteria in Lung Cancer (2).

Answer 22

1. 2WR : CXR Findings or 40+ and Unexplained Haemoptysis.

2. Offer URGENT CXR if 40+ and : 2+ unexplained symptoms or smoked and 1+ unexplained symptom.

Question 23

Blood Findings in Lung Cancer.

Answer 23

Thrombocytosis.

Question 24

Biopsies in Lung Cancer (2).

Answer 24

1. Central Lesions - Bronchoscopy.

2. Peripheral Lesions - CT-Guided Sampling.

Question 25

Management of NSC Lung Cancer (4).

Answer 25

1. MDT Meeting. 2. Surgery - 1st Line (if disease is isolated to a single area) : Lobectomy (or Segmentectomy / Wedge Resection). 3. Radiotherapy - curative if early. 4. Chemotherapy - Adjuvant or Palliative.

Question 26

Management of SC Lung Cancer (2).

Answer 26

1. Chemotherapy + Radiotherapy. | 2. Palliative : Endobronchial Treatment with Stents/Debulking for Bronchial Obstruction.

Question 27

Surgery in NSC Lung Cancer.

Answer 27

1. Mediastinoscopy prior to surgery because CT may not show mediastinal lymph node involvement. 2. Contraindications : Stage IIIB, IV; FEV < 1.5L; Malignant Effusion, Hilar Tumour, Vocal Cord Paralysis, SVC Obstruction.

Question 28

Prognosis of Lung Cancer.

Answer 28

SC < NSC.

Question 29

What is a Paraneoplastic Syndrome?

Answer 29

Syndrome caused by substances produced by tumour cells that act remotely from the tumour or its metastases.

Question 30

Why is Lung Cancer associated with Recurrent Pneumonia?

Answer 30

Tumours may partially obstruct airways, leading to poor ventilation and increased susceptibility.