Respiratory Systems 6 - Respiratory Pathology

Question 1

How common is lung cancer in the uk?

Answer 1

• It is the 4th common cause of death in the UK - and accounts for 40,000 deaths
• Kills more women than breast cancer

Question 2

How many people die 1 year after lung cancer diagnosis?

Answer 2

80% in patients with advanced disease, where curative treatment cannot be used

Question 3

List the causative factors of lung cancer.

Answer 3

• Tobacco
• Radon
• Asbestos

Question 4

List the clinical features of lung cancer.

Answer 4

• Haemoptysis
• Unexplained or persistent (>3 weeks) cough, chest/shoulder pain, dyspnoea, hoarseness.
• Finger clubbing

Question 5

What is the choice of treatment of lung cancer dependent upon?

Answer 5

• Histological cell type
• The stage of the lung cancer
• Performance status of the patient

Question 6

What are non-small cell lung cancers?

Answer 6

• 75% of all lung cancers
• Consists of squamous cell carcinoma, large cell carcinoma, anaplastic carcinoma, adenocarcinoma, and bronchiolo-alveolar cell carcinoma

Question 7

Describe the multistep theory of tumour development.

Answer 7

Cancers arise as a consequence of accumulation of mutations of genes which regulate cell proliferation, invasion, angiogenesis and senescence.

Question 8

What is the precursor lesion for squamous cell carcinomas?

Answer 8

• Squamous metaplasia becomes dysplasia, which results in carcinoma in situ
• Specific genes are mutated in different stages of development

Question 9

What is the precursor of adenocarcinoma?

Answer 9

Atypical adenomatous hyperplasia

Question 10

Why do some smokers not get lung cancer?

Answer 10

This may be due to the lack of specific polymorphisms that affect the risk of developing lung cancer

Question 11

List the main types of lung cancer and the percentage of lung cancer they make up.

Answer 11

• 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

Question 12

Describe the behaviour of squamous cell carcinomas.

Answer 12

• Mainly central

- Distal spread is seen later than in adenocarcinomas

Question 13

Describe the behaviour of adenocarcinomas

Answer 13

Often peripheral

Question 14

Describe the behaviour of small cell carcinomas

Answer 14

Very aggressive behaviour

Question 15

List the local complications of lung cancer

Answer 15

• Airway obstruction

- Local invasion

Question 16

List the systemic complications of lung cancer

Answer 16

• Metastases
• Paraneoplastic syndromes (expression of substances such as hormones by the tumour despite the original cell type not producing that substance)

Question 17

How is lung cancer diagnosed?

Answer 17

• Cytology (study of cells - look for malignant cells in sputum or from bronchoscophy)
• Histology (looking at tissues from biopsy)
• Gene profiling

Question 18

How does staging occur?

Answer 18

• All patients have a CT scan of the thorax, liver and adrenals
• May also be a bone scan, or PET scan
• Classified using TNM

Question 19

Describe tumour classification of lung cancer in the TNM system.

Answer 19

• TX cannot be assessed
• T0 no evidence
• Tis (carcinoma in situ)
• T1 tumour 3cm/

Question 20

Describe the lymph node classification of lung cancer in the TNM system.

Answer 20

• 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)

Question 21

Describe the metastasis classification of lung cancer in the TNM system.

Answer 21

• 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)

Question 22

Summarise the treatment of small cell lung cancer

Answer 22

• Highly responsive to chemo and radiotherapy

- Combination chemotherapy is required due to the speed at which metastasis occurs

Question 23

Summarise the treatment of non-small cell lung cancer

Answer 23

• Surgery considered in stage 1, 2 and 3 disease
• Chemotherapy offered with concomitant radiotherapy before surgery
• Advanced disease requires palliation

Question 24

What determines lung cancer survival?

Answer 24

• Ability to operate

- 5% surgical risk 10% major complications

Question 25

What is mesothelioma?

Answer 25

• 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.

Question 26

Describe the pathophysiology of mesothelioma

Answer 26

• 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.

Question 27

Give some examples of paraneoplasmic syndromes

Answer 27

• Cushing syndrome (ACTH caused by small cell carcinoma)
• Hypercalcaemia (small cell carcinoma)
• Hyponatremia (inappropriate ADH secretion)