Orientation notes for study. Treatment is decided by a multidisciplinary team; check current oncology guidelines.
Definition and epidemiology
Lung cancer is a malignant tumour arising from the bronchial epithelium (bronchogenic carcinoma). It is the leading cause of cancer death worldwide. Most patients present late with advanced disease, which is the main reason for poor survival (5-year survival about 15–20%).
Risk factors
- Smoking (about 85–90% of cases; risk rises with pack-years; stopping lowers risk over time).
- Passive smoking.
- Occupational: asbestos, silica, radon, arsenic, chromium, nickel, diesel exhaust.
- Biomass fuel smoke and air pollution (important in Kenya, especially adenocarcinoma in women who never smoked).
- Pre-existing lung disease: COPD, pulmonary fibrosis, previous TB scarring.
- Family history and genetic susceptibility; previous radiation; HIV infection.
Pathology
| Type | Features |
|---|---|
| Non-small cell lung cancer (NSCLC) ≈ 85% | |
| • Adenocarcinoma | Commonest overall; peripheral; women and never-smokers; often EGFR, ALK, ROS1 mutations; mucin production; metastasises early to bone and brain |
| • Squamous cell carcinoma | Central near the hilum; smokers; cavitation; keratin; PTHrP secretion causing hypercalcaemia |
| • Large cell carcinoma | Peripheral, undifferentiated |
| Small cell lung cancer (SCLC) ≈ 15% | Central; very strong smoking link; neuroendocrine origin; very rapid growth and early metastasis; paraneoplastic syndromes (ectopic ACTH, SIADH, Lambert–Eaton); chemotherapy-sensitive |
| Others | Carcinoid, mesothelioma (pleura), metastases from elsewhere (commonest lung malignancy overall) |
Clinical features
- Local (intrathoracic): persistent cough (over 3 weeks, change in a smoker's cough), haemoptysis, dyspnoea, chest pain, recurrent or non-resolving pneumonia, wheeze, weight loss and anorexia.
- Regional spread:
- Recurrent laryngeal nerve → hoarse voice (left side).
- Phrenic nerve → diaphragm paralysis.
- Superior vena cava obstruction (SVCO) → facial swelling, distended neck veins, headache, collateral veins (an emergency).
- Pancoast tumour (apex): shoulder and arm pain (C8–T1), Horner's syndrome (ptosis, miosis, anhidrosis), wasting of the small hand muscles.
- Pleural effusion, pericardial effusion, dysphagia (oesophagus).
- Distant metastases: bone (pain, pathological fracture, hypercalcaemia), brain (headache, seizures, focal signs), liver, adrenals.
- Paraneoplastic syndromes:
- SCLC: SIADH (hyponatraemia), ectopic ACTH (Cushing's), Lambert–Eaton myasthenic syndrome.
- Squamous: hypercalcaemia (PTHrP).
- Clubbing, hypertrophic pulmonary osteoarthropathy, thrombophlebitis, dermatomyositis, neuropathy.
- Examination: cachexia, clubbing, cervical and supraclavicular nodes, signs of effusion or collapse, hepatomegaly.
Investigations
- Chest X-ray: mass, collapse, effusion, hilar enlargement, cavitating lesion, nodule. A normal X-ray does not exclude cancer.
- Contrast CT chest and upper abdomen: tumour and nodes, adrenals and liver.
- Tissue diagnosis (essential):
- Bronchoscopy (central tumours), EBUS (nodes), CT-guided percutaneous biopsy (peripheral), pleural fluid cytology or biopsy, node biopsy.
- Molecular testing in adenocarcinoma: EGFR, ALK, ROS1, PD-L1.
- Staging: PET-CT, brain MRI/CT, bone scan; TNM staging; blood tests (FBC, LFTs, calcium, sodium, ALP).
- Fitness for treatment: spirometry and DLCO, performance status (ECOG), cardiac assessment.
- Always exclude TB (and fungal disease) in Kenya, since TB can mimic or coexist with lung cancer.
Management
NSCLC (stage-based):
- Stage I–II (operable): surgery (lobectomy) with nodal sampling, or stereotactic radiotherapy (SBRT) if unfit; adjuvant chemotherapy for some.
- Stage III: chemoradiotherapy ± immunotherapy.
- Stage IV: systemic therapy: targeted (EGFR, ALK inhibitors), immunotherapy (PD-1/PD-L1 inhibitors), platinum chemotherapy; palliative radiotherapy.
SCLC:
- Limited stage: platinum–etoposide chemotherapy + thoracic radiotherapy, and prophylactic cranial irradiation.
- Extensive stage: chemotherapy ± immunotherapy; palliative radiotherapy.
- Very chemosensitive but relapses quickly.
Palliative and supportive care (for all): analgesia (WHO ladder, opioids), radiotherapy for bone pain, haemoptysis, SVCO, brain metastases; SVC stenting; drain or pleurodesis for effusions; oxygen; steroids for SVCO or cord compression; management of hypercalcaemia and SIADH; psychological support; end-of-life care and early palliative involvement.
Emergencies: SVC obstruction, spinal cord compression, hypercalcaemia, massive haemoptysis, tracheal obstruction.
Prevention
- Do not smoke; stop smoking (cessation at any age helps).
- Reduce biomass smoke (clean cookstoves, ventilation), enforce occupational controls (asbestos, silica).
- Low-dose CT screening in some countries for high-risk smokers (aged 50–80 with 20 or more pack-years): limited availability in Kenya.
Prognosis
- Depends on stage, cell type, performance status. SCLC has a worse prognosis (untreated median survival of a few months).
- Early detection of a chronic cough, haemoptysis and weight loss in smokers and in anyone with unresolved symptoms is the best chance of cure.
Exam points
- Adenocarcinoma is the commonest type; squamous is central and gives hypercalcaemia; small cell is central with paraneoplastic SIADH and ACTH and is treated with chemotherapy, not surgery.
- Pancoast tumour → Horner's syndrome and arm pain.
- Tissue diagnosis before treatment.
- In Kenya, think TB and cancer in a chronic cough or haemoptysis.
- Stage decides treatment.
Pharmacology at a glance
Tap a drug name for its full card (how it works, adverse effects, cautions, dose), then use Back to this note to return to this spot. Condition guide: lung cancer drugs.
| Drug | Class | Role here | Watch for |
|---|---|---|---|
| Cisplatin | Platinum chemotherapy | Backbone of non-small cell and small cell regimens | Kidney damage, hearing loss, severe vomiting, low magnesium |
| Carboplatin | Platinum chemotherapy | Used when kidney function is poor or cisplatin is not tolerated | Low platelets and white cells |
| Etoposide | Topoisomerase II inhibitor | With a platinum drug in small cell lung cancer | Low blood counts, hair loss |
| Osimertinib | EGFR tyrosine kinase inhibitor | EGFR-mutant adenocarcinoma | Rash, diarrhoea, interstitial lung disease |
| Pembrolizumab | PD-1 checkpoint inhibitor | High PD-L1 non-small cell lung cancer | Immune-related colitis, pneumonitis, thyroid disease |
| Dexamethasone | Corticosteroid | Brain metastases, cord compression, SVC obstruction | High glucose, mood change, infection |
| Morphine | Opioid analgesic | Cancer pain and breathlessness | Constipation, drowsiness; give a laxative |
| Zoledronic acid | Bisphosphonate | Bone metastases and hypercalcaemia | Jaw osteonecrosis, kidney function |
| Ondansetron | 5-HT₃ antagonist | Chemotherapy-induced vomiting | Constipation, QT prolongation |
Test before you treat: the tissue type and the EGFR, ALK and PD-L1 results decide which drug is used.
Practice questions
1. A 60-year-old smoker has hyponatraemia (Na 118) with low serum osmolality and concentrated urine, with a central lung mass. The most likely tumour is: A. Adenocarcinoma · B. Squamous cell carcinoma · C. Small cell carcinoma (SIADH) · D. Large cell carcinoma · E. Mesothelioma Answer: C.
2. A man has right shoulder pain radiating down the arm, miosis, ptosis and anhidrosis. The likely lesion is: A. Cervical rib · B. Pancoast tumour at the lung apex · C. Brachial neuritis · D. Mediastinal mass · E. Rotator cuff tear Answer: B.
3. A smoker has hypercalcaemia, a central cavitating hilar mass, with low PTH and raised PTHrP. The most likely histology is: A. Small cell · B. Adenocarcinoma · C. Squamous cell carcinoma · D. Carcinoid · E. Large cell Answer: C.