Lung Cancer

Classification

Small Cell Lung Cancer (SCLC)

•    ~15% of lung cancers

•    Central, rapidly growing, early metastases (brain, liver, bone, adrenals)

•    Almost always linked to smoking

Non-Small Cell Lung Cancer (NSCLC) (~85%)

•    Squamous cell carcinoma

o    Central location

o    Cavitating masses

o    Associated with hypercalcaemia (PTHrP production)

o    Strong smoking link

•    Adenocarcinoma

o    Peripheral

o    Most common lung cancer in non-smokers and women

o    Can present as solitary pulmonary nodule

•    Large cell carcinoma

o    Peripheral or central

o    Poorly differentiated, aggressive

Paraneoplastic Syndromes

•    SCLC:

o    SIADH → hyponatraemia (euvolaemic)

o    Ectopic ACTH → Cushing’s syndrome

o    Lambert–Eaton myasthenic syndrome (LEMS)

•    Squamous cell carcinoma:

o    Hypercalcaemia (PTHrP)

•    Others:

o    Hypertrophic pulmonary osteoarthropathy (HPOA) → clubbing, periostitis

o    Dermatomyositis/polymyositis

Diagnosis and Staging

•    Initial: CXR (non-specific; mass, collapse, effusion)

•    CT thorax: detailed assessment of primary tumour and nodes

•    PET-CT: distant metastases (staging)

•    Tissue diagnosis:

o    Central tumours → bronchoscopy ± endobronchial biopsy

o    Peripheral tumours → CT-guided biopsy

Management

•    SCLC: chemotherapy ± radiotherapy; surgery rarely used due to early spread

•    NSCLC:

o    Early-stage → surgery ± adjuvant therapy

o    Advanced → chemotherapy, targeted therapy (EGFR inhibitors if EGFR+, ALK inhibitors)

Mesothelioma

Features

•    Malignant tumour of pleura, almost always linked to asbestos exposure

•    Long latency (decades after exposure)

Clinical

•    Dyspnoea, pleuritic chest pain

•    Recurrent unilateral effusion

•    Weight loss

Imaging

•    CXR: unilateral effusion, diffuse pleural thickening

•    CT: pleural thickening, nodularity

Diagnosis

•    Pleural biopsy (thoracoscopy)

Prognosis

•    Very poor; median survival ~1 year

Management

•    Palliative: pleurodesis, analgesia

•    Chemotherapy: pemetrexed + cisplatin

Mediastinal Tumours

Anterior mediastinum ("4 T's")

•    Thymoma:

o    Associated with myasthenia gravis

o    Also red cell aplasia, hypogammaglobulinaemia

•    Teratoma/germ cell tumours

•    Thyroid goitre

•    Terrible lymphoma

Middle mediastinum

•    Lymphadenopathy (sarcoidosis, lymphoma, metastases)

•    Bronchogenic cysts

Posterior mediastinum

•    Neurogenic tumours (schwannomas, neurofibromas)

•    Oesophageal lesions

Extra Revision Pearls

•    SCLC → central, "smoking, SIADH, Small cell, Speedy spread"

•    Adenocarcinoma → peripheral, non-smokers

•    Squamous → central, cavitating, calcium

•    Mesothelioma → pleural plaques clue, long latency

•    Thymoma → strongly think myasthenia gravis if mediastinal mass + weakness

•    Hypertrophic pulmonary osteoarthropathy → clubbing + periostitis = lung cancer clue

•    Pancoast tumour (superior sulcus): shoulder pain, Horner’s syndrome, brachial plexopathy