7 Respiratory Pathology: Lung Cancer Flashcards
Q: In terms of most common cause of death in the UK, what place is cancer? What’s mortality within 1 year of diagnosis? 5 yr survival? What needs to happen for better prognosis? How do lung cancer rates vary globally?
A: 3rd
80%
5.5%
detect early
decreasing in developed world by increasing in non
Q: Name causative factors of cancer. (5) What do lung cancer trends follow? Therefore?
A: tobacco (++ carcinogens in smoke) radiation (e.g.) radon asbestos genetic predisposition other (e.g. heavy metals)
- lung cancer trends follow smoking prevalence
- ++ health outcomes with earlier cessation of smoking
Q: What are the clinical features of cancer? (6)
A: - haemoptysis: coughing up blood
- unexplained or persistent (3+ wks): cough
- unexplained or persistent (3+ wks) chest/ shoulder pain
- ” dyspnoea
- ” hoarseness
- finger clubbing
Q: What occurs if someone is thought to have lung cancer?
A: urgent referral for a chest X ray (CXR)
Q: Clinical history: 74 yr old male; 6 month h/o weight loss, lethargy, – appetite; haemoptysis; good performance status; smoker equivalent of 70 pack yrs; no occupational risk factors; clubbing of finger nails, nicotine staining, cachexia, diminished air entry right base.
What should happen next? (7) Finally?
A: 1. CXR
2. bronchoscopy/ CT/ lymph node biopsy (take samples when do bronchoscopy); PET scan
staging TNM classification (tumour (T1-4)- location and size, 1-4; lymph nodes (N0-3), 0-3; metastases (M0-1), 0-1)
fitness
treatment
Q: What does histopathology involve? (5) Aim?
A: confirm diagnosis;
type; stage; molecular pathology; cytology; histology (biopsy/ surgical biopsy)
Q: Summarise the type of system the airways are? How wide are bronchi? bronchiole? small airways? Role of small airways? What prevents the collapse of trachea?
A: - airway conductive system (asymmetrical dichotomous branching tubular system up to 24 times)
bronchi >1mm; bronchiole <1mm; small airways <2mm (conduct to alveoli)
cartilage prevents collapse
Q: What does the gas exchange compartment contain? (4) Where do tumours occur?
A: (alveoli)
airways; alveolar parenchyma (epithelium/ interstitium); vasculature (arteries/ veins/ lymphatics); pleura
anywhere
Q: By which type of pathway do carcinomas develop? Result in? (4) Where do mutations occur? (2)
A: multistep accumulation of mutations resulting in:
o disordered growth
o loss of cell adhesion (less organised structures)
o invasion of tissue by tumour
o simulation of new vessel formation around tumours
- mutations occur in epithelial cells and stem cells
Q: What is reflected in the histology of tumours?
A: different tumour types
Q: Which cells in the lung do tumours tend to arise from? (3) What are the 2 types? How do these types differ? (2) 2 examples. What is the most common type of lung cancer?
A: epithelial, mesenchymal (soft tissue), lymphoid
- benign: do not metastasise; can cause local complications (e.g. airway obstruction); e.g. chondroma
- malignant: potential to metastasise; variable clinical behaviour; commonest: epithelial tumours->carcinomas
Q: What is the most common type of lung cancer? What percentage of all lung cancer cases does it make up? 3 subtypes? Give occurrence rate of 2 of them.
A: Non-small cell lung cancer
about85%
Squamous cell carcinoma, adenocarcinoma, and large cell carcinoma
- squamous cell carcinoma (20-40%)
- adenocarcinoma (20-40%)
Q: What is the 5 year survival rate for early stage non-small cell carcinoma? Late stage? What can some people be offered if they have early stage non-small cell carcinoma? reason?
A: early stage 1: 60% 5 yr survival
late stage: 5% 5 yr survival
20-30% have early stage tumours suitable for surgical resection
o less chemosensitive
Q: What type of pathway leads to the development of squamous cell carcinoma? What is this a subtype of? What is squamous cell carcinoma closely related to? What is a key feature that means early detection is beneficial?
A: multi-step pathway of development
Non-small cell lung cancer
closely associated with smoking
local spread, metastasise late
Q: Where does squamous cell carcinoma manifest? (traditionally and now) Explain the pathway for development. (5) What can it lead it? What type of treatment can you get? downside?
A: proximal airways- traditionally central arising from bronchial epithelium, but recent increase in peripheries (smoking changes)
- ciliated respiratory epithelium exposed to recurrent irritation
- metaplasia
- squamous epithelium (X mucous clearing) -> more unstable
- dysplasia -> ability to invade surrounding tissue
- carcinoma
- keratinisation
- may develop fatal haemorrhage with anti-angiogenic therapy
Q: In what group of people is adenocarcinoma most common? How does this vary? (3) How has incidence changed over time? Where does it manifest itself in terms of airways?
A: commonest type in non-smokers
- commoner in far east, females and non-smokers
- increasing incidence
- distal airways and alveolar epithelium; more often multicentric
Q: What is specific to adenocarcinomas? (3) When is this form of cancer curative? What is common and early? What does histology show?
What is the target for treatment?
A: atypical adenomatous hyperplasia: proliferation of atypical cells lining the alveolar walls -> ++ size -> invasive
• early resection before invasion -> curative
• commoner in far east, females and non-smokers
• extrathoracic metastases common and early
• histology shows evidence of glandular differentiation
• variety of molecular abnormalities provide targets for treatment
Q: Describe the incidence of large cell carcinoma. How has incidence changed over time? What can cause it? Describe it.
A: uncommon
• decreasing in incidence
• occupational exposure etc.
• poorly differentiated tumours of large cells
