Lung Cancer
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Lung Cancer is the leading cause of cancer death worldwide. It is broadly divided into Non-Small Cell Lung Cancer (NSCLC) (85%) and Small Cell Lung Cancer (SCLC) (15%).
Key Classification
| Type | Subtypes | Characteristics |
|---|---|---|
| NSCLC (85%) | Adenocarcinoma | Most common. Peripheral. Common in non-smokers. |
| Squamous Cell | Central. Smokers. Cavitates. Releases PTHrP (Hypercalcaemia). | |
| Large Cell | Peripheral. Poor prognosis. | |
| SCLC (15%) | Small Cell | Central. Neuroendocrine. Smokers. Very aggressive. Early metastasis. Paraneoplastic syndromes (SIADH/ACTH). |
Clinical Scenario: The Hoarse Smoker
A 65-year-old heavy smoker presents with a 4-week history of a hoarse voice and a 'bovine' cough. He has lost 5kg.
Key Teaching Points
- Hoarseness implies **Recurrent Laryngeal Nerve palsy** (left side commoner due to aortic loop).
- A 'Bovine cough' (non-explosive) confirms loss of vocal cord adduction.
- This indicates a tumour in the Aorto-pulmonary window (inoperable T4 disease).
- Urgent Chest X-ray and CT scan required.
Image Integration Plan
| Image Type | Source | Status |
|---|---|---|
| Management Algorithm | AI-generated | PENDING |
| Pathophysiology (Genetic Mutations) | AI-generated | PENDING |
| CXR (Cannonball Metastases) | Web Source | PENDING |
| CT Chest (Spiculated Mass) | Web Source | PENDING |
[!NOTE] Image Generation Status: Diagrams illustrating the 'Pancoast Tumour' and Horner's Syndrome pathway are queued.
Staging (TNM 8)
- T: Size and invasion.
- N: Nodes (Hilar -> Mediastinal -> Supraclavicular).
- M: Metastasis (Brain, Bone, Liver, Adrenals).
- Risk Factors:
- Smoking: Responsible for 90% of cases. (Risk correlates with Pack Years).
- Asbestos: Mesothelioma and Lung Cancer (synergistic risk with smoking).
- Radon Gas.
- Occupational: Silica, Diesel exhaust.
- Genetics: EGFR mutations (more common in Asian female non-smokers).
- Driver Mutations: EGFR, ALK, ROS1, KRAS, PD-L1.
- Metastasis:
- Lymphatic: Hilar nodes.
- Haematogenous: Liver, Adrenals, Bone, Brain.
Local Symptoms
Regional Invasion
Paraneoplastic Syndromes
- Hands: Clubbing, Tar staining, HPOA tenderness. Wasting of intrinsic muscles (Pancoast).
- Neck: Lymphadenopathy (Supraclavicular), JVP (SVCO).
- Chest:
- Collapse: Reduced expansion, Dull, Reduced breath sounds.
- Effusion: Stony dullness.
- Fibrosis (post-radiotherapy).
- Abdomen: Hepatomegaly (mets).
Diagnosis
- CXR: First line. (Coin lesion, hilar enlargement, effusion, collapse).
- CT Chest/Abdomen (Contrast): Staging.
Tissue Diagnosis (Essential)
- Bronchoscopy: For central tumours. (Biopsy/Washings).
- EBUS (Endobronchial Ultrasound): For mediastinal lymph nodes.
- CT-Guided Biopsy: For peripheral lesions.
Functional (For Surgery Fitness)
- PET Scan: To rule out occult metastases.
- Lung Function Tests (Spirometry): Can they tolerate a lobectomy? (FEV1 > 1.5L usually required).
Discussed in MDT (Multidisciplinary Team).
A. Non-Small Cell (NSCLC)
- Surgery (Gold Standard for Stage I-II):
- Lobectomy: Removal of lobe.
- Pneumonectomy: Removal of whole lung.
- Wedge Resection: For poor lung function.
- Radical Radiotherapy (SABR):
- Stereotactic Ablative Radiotherapy. Curative intent for small tumours in patients unfit for surgery.
- Systemic Therapy (Stage III-IV):
- Targeted Therapy: If EGFR+ (Osimertinib), ALK+ (Alectinib).
- Immunotherapy: PD-L1 inhibitors (Pembrolizumab).
- Chemotherapy: Platinum doublets.
B. Small Cell (SCLC)
Usually disseminated at presentation. Surgery rarely an option.
- Chemotherapy: Cisplatin + Etoposide (highly responsive initially but relapses).
- Radiotherapy: Thoracic radiation + Prophylactic Cranial Irradiation (PCI) (to prevent brain mets).
- SVCO: Medical emergency. Rx: Dexamethasone + Stent.
- Spinal Cord Compression.
- Hypercalcaemia.
- Massive Haemoptysis.
- Overall 5-year survival: ~15-20% (improving with immunotherapy).
- Stage I: >60%.
- Small Cell: Very poor (<5% 5-year survival).
- NICE NG122: Lung Cancer: diagnosis and management.
- Pacific Trial: Durvalumab after chemoradiotherapy improves survival in Stage III NSCLC.
What are the types?
- Non-Small Cell: Grow more slowly. Often cured if caught early.
- Small Cell: Grow very fast and spread quickly. Treated mainly with strong chemotherapy.
Is it always from smoking? About 90% is. But people who never smoked can get it (usually a specific type called Adenocarcinoma), and we have new "smart drugs" (targeted tablets) that work very well for these people.
What is the treatment?
- Surgery: Cutting out the cancer (lobectomy). Best chance of cure.
- Radiotherapy: High energy X-rays to zap the tumour (SABR).
- Chemotherapy: Drips to kill cancer cells.
- Immunotherapy: New drips that take the "brakes" off your own immune system so it can attack the cancer.
What is the outlook? It depends heavily on the stage. If caught early before it spreads, it is curable. If it has spread, we treat it as a chronic condition to keep it under control for as long as possible.
- NICE. Lung cancer: diagnosis and management [NG122]. 2019.
- Antonia SJ, et al. Durvalumab after Chemoradiotherapy in Stage III Non-Small-Cell Lung Cancer. N Engl J Med. 2017.
- Garon EB, et al. Pembrolizumab for the treatment of non-small-cell lung cancer. N Engl J Med. 2015.