Lung Cancer Flashcards
Definition of lung cancer (different types)
Malignant neoplasm of the lung that typically arises from the epithelial cells of the lower respiratory tract.
Lung cancer is made up of a few different conditions:
• Non-Small cell lung cancer: (80% of lung cancers)
◦ Much more common
◦ Adenocarcinoma (45%)
◦ Squamous cell carcinoma (30%)
◦ Large cell carcinoma (10%)
• Small cell lung cancer (20%)
◦ Small and densely packed tumour cells with scant cytoplasm, finely granular nuclear chromatin and absence of nucleoli
Risk factors of lung cancer
Risk factors:
• Smoking/Tobacco exposure: biggest risk factor, also includes passive smoking
• Asbestos exposure
• Radon
• Chronic lung diseases (e.g COPD, fibrosis)
• Immunodeficiency
• Family history/Genetic (e.g alpha 1 antitrypsin deficiency)
Pathophysiology of lung cancers
• Adenocarcinomas:
◦ They are the most common type of non-small cell lung cancer
◦ Located more peripherally in the lung
◦ Originate from the mucus producing glandular tissue
• Squamous cell lung cancer:
• 2nd most common NSCLC
• Located more centrally, involving the bronchial epithelium of the central airways
• Thought to metastasise later in the disease course
• Large cell lung cancer:
‣ Heterogenous group (mixed), tends to arise centrally
‣ Undifferentiated
• Small cell lung cancer:
‣ Highly associated with smoking
‣ Tend to arise in the central lung with mediastinal involvement (affects the pulmonary neuroendocrine cells)
‣ Highly malignant (high chance of distant metastases
• Tyrosine kinase can be abnormal in lung cancer; hence can be a target for therapeutic action
History and examination of lung cancer
• Asymptomatic: may have a late presentation or be detected incidentally
• Cough
• Dyspnoea/SOB
• Haemoptysis: can be blood tinged sputum, unlikely to be massive haemoptysis
• Weight loss
• Fatigue
• Chest and/or shoulder pain
• Male sex, 65-70
• Finger clubbing
• Lung sounds
• Lymphadenopathy
• Bone pain: due to metastases
• Horner’s syndrome: tumour compressing the sympathetic tract leading to ptosis, anhydrosis, miosis etc
• Cachexia
• Pemberton’s sign: compression of the superior vena cava which reduces venous return (worse when arms lifted)
Investigations for lung cancer
• Chest X ray: May be able to detect mass in lung, consolidation, hilar enlargement, lung collapse, pleural effusion etc
• Contrast CT chest + abdo: allows for staging of the cancer. Can show size, location, lymph node involvement and possible metastases
For biopsy:
• Bronchoscopy: for tumours of central airways (likely to detect squamous cell carcinomas)
• CT guided lung biopsy: to access peripheral lung tumours (e.g adenocarcinomas)
• Endobrachial ultrasound and transbronchial needle: aspirates the lymph nodes
• Can do PET scan: to rule out metastases
• Sputum cytology: may be able to detect malignant cells
May have anaemia of chronic disease and raised CRP
Treatment for lung cancer
For early disease:
1) Surgery: If patient fit for surgery, this should be the first option
‣ Resect the tumour, usually needs a lobectomy and lymphadenectomy
‣ Can be done laproscopically due to decreased risks
More advanced stages that include lymph nodes may require preoperative chemotherapy/radiotherapy
If NOT suitable for surgery:
1) Radical Radiotherapy: good outcomes due to high precision
For metastatic NSCLC with mutation:
1) Oncogene directed: tyrosine kinase inhibitors (would target the mutated genes)
For metastatic NSCLC with NO mutation (and PDL1 >50%):
1) Immunotherapy: drugs can block the PDL1 receptor
For metastatic NSCLC with no mutation and PDL1<50%:
1) Cytotoxic chemotherapy and immunotherapy: has significant side effects
Prevention and prognosis of lung cancer
Smoking cessation, prevent occupational exposure of carcinogens
prognosis dependent on stage. Small cell lung cancer has lower survival if left untreated
Complications of lung cancer
• Post obstructive pneumonia
• Paraneoplastic syndromes
• Chemotherapy induced symptoms
• Superior vena cava syndrome
