Respiratory Systems 6 - Respiratory Pathology Flashcards
How common is lung cancer in the uk?
- It is the 4th common cause of death in the UK - and accounts for 40,000 deaths
- Kills more women than breast cancer
How many people die 1 year after lung cancer diagnosis?
80% in patients with advanced disease, where curative treatment cannot be used
List the causative factors of lung cancer.
- Tobacco
- Radon
- Asbestos
List the clinical features of lung cancer.
- Haemoptysis
- Unexplained or persistent (>3 weeks) cough, chest/shoulder pain, dyspnoea, hoarseness.
- Finger clubbing
What is the choice of treatment of lung cancer dependent upon?
- Histological cell type
- The stage of the lung cancer
- Performance status of the patient
What are non-small cell lung cancers?
- 75% of all lung cancers
- Consists of squamous cell carcinoma, large cell carcinoma, anaplastic carcinoma, adenocarcinoma, and bronchiolo-alveolar cell carcinoma
Describe the multistep theory of tumour development.
Cancers arise as a consequence of accumulation of mutations of genes which regulate cell proliferation, invasion, angiogenesis and senescence.
What is the precursor lesion for squamous cell carcinomas?
- Squamous metaplasia becomes dysplasia, which results in carcinoma in situ
- Specific genes are mutated in different stages of development
What is the precursor of adenocarcinoma?
Atypical adenomatous hyperplasia
Why do some smokers not get lung cancer?
This may be due to the lack of specific polymorphisms that affect the risk of developing lung cancer
List the main types of lung cancer and the percentage of lung cancer they make up.
- Squamous cell carcinomas make up 25-40% of lung cancers, and have strong association with smoking
- Adenocarcinomas 25-40% of lung cancer, incidence is increasing. Most common type in non-smokers
- Small cell carcinomas are 20-25% of lung cancer, have a strong association with smking
Describe the behaviour of squamous cell carcinomas.
- Mainly central
- Distal spread is seen later than in adenocarcinomas
Describe the behaviour of adenocarcinomas
Often peripheral
Describe the behaviour of small cell carcinomas
Very aggressive behaviour
List the local complications of lung cancer
- Airway obstruction
- Local invasion
List the systemic complications of lung cancer
- Metastases
- Paraneoplastic syndromes (expression of substances such as hormones by the tumour despite the original cell type not producing that substance)
How is lung cancer diagnosed?
- Cytology (study of cells - look for malignant cells in sputum or from bronchoscophy)
- Histology (looking at tissues from biopsy)
- Gene profiling
How does staging occur?
- All patients have a CT scan of the thorax, liver and adrenals
- May also be a bone scan, or PET scan
- Classified using TNM
Describe tumour classification of lung cancer in the TNM system.
- TX cannot be assessed
- T0 no evidence
- Tis (carcinoma in situ)
- T1 tumour 3cm/
Describe the lymph node classification of lung cancer in the TNM system.
- NX cannot be assessed
- N0 No regional lymph node metastasis
- N1 Metastasis in ipsilateral peribronchial and/or ipsilateral hilar lymph nodes, including direct extension
- N2 Metastasis in ipsilateral mediastinal and/or subcarinal lymph node(s)
- N3 Metastasis in contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene or supraclavicular lymph node(s)
Describe the metastasis classification of lung cancer in the TNM system.
- MX cannot be assessed
- M0 No distant metastasis
- M1 Distant metastasis Note: M1 includes separate tumour nodule(s) in a different lobe (ipsilateral or contralateral)
Summarise the treatment of small cell lung cancer
- Highly responsive to chemo and radiotherapy
- Combination chemotherapy is required due to the speed at which metastasis occurs
Summarise the treatment of non-small cell lung cancer
- Surgery considered in stage 1, 2 and 3 disease
- Chemotherapy offered with concomitant radiotherapy before surgery
- Advanced disease requires palliation
What determines lung cancer survival?
- Ability to operate
- 5% surgical risk 10% major complications
What is mesothelioma?
- Mesothelioma is a type of cancer that develops in the lining that covers the outer surface of the pleura or the peritoneum.
- It’s usually linked to asbestos exposure.
Describe the pathophysiology of mesothelioma
- When asbestos fibers are breathed in, they travel to the ends of small air passages and reach the pleura, where they can cause inflammation and scarring.
- This may damage cells’ DNA.
- If swallowed, these fibers can reach the abdominal lining.
Give some examples of paraneoplasmic syndromes
- Cushing syndrome (ACTH caused by small cell carcinoma)
- Hypercalcaemia (small cell carcinoma)
- Hyponatremia (inappropriate ADH secretion)
