7 - Respiratory Pathology

Question 1

What is the most common cause of lung cancer?

Answer 1

smoking (contains carcinogens)

Question 2

what is the first diagnostic test used for lung cancer?

Answer 2

chest x-ray or CT scan

subtle symptoms—–> chest x-ray
major symptoms/over the age of 50—–> CT scan

Question 3

What are the clinical features of lung cancer?

Answer 3

haemoptysis 
finger clubbing
cough
shoulder/chest pain
dyspnoea
hoarseness

Question 4

What test is done to get a sample of the tumour?

Answer 4

bronchoscopy

NOTE: sample the tumour with the highest staging

Question 5

What is the first thing to look at when you have a sample of a tumour?

Answer 5

is it small cell or non-small cell cancer?

Question 6

What classification is used to stage tumours? What does this represent?

Answer 6

TNM classsification
TUMOUR
-size of the tumour
-where it is located
- adjacent structures
NODE
- if tumour has spread to lymph nodes
METASTASES
- if the tumour has spread to other organs

Question 7

Why would a PET scan be used?

Answer 7

shows activity

allows us to see the spread of suspected tumour to other organs

Question 8

what is a trans-thoracic CT biopsy?

give some advantages and disadvantages

Answer 8

a needle is inserted into the chest guided by a CT scan

/ real time
/ sensitivity 70-100%
x risk of pneumothorax
x small sample area
x in case of bleeding, there is no immediate intrabrochial treatment possible

Question 9

If the tumour is local, what is the best treatment?

Answer 9

Surgery

Question 10

If there is advanced disease with lymph node involvement, what is the best treatment?

Answer 10

Start with chemotherapy to try and reduce the extent of spread

Question 11

What is minimum length of a tumour at which it can be detected?

Answer 11

10 mm

Question 12

Why is lung cancer hard to detect?

Answer 12

Most patients are asymptomatic

Question 13

what are histology and cytology?

Answer 13

histology - looking at tissues

cytology - looking at individual cells

Question 14

what is the most common type of malignant lung tumour?

Answer 14

epithelial tumours

Question 15

other than smoking, what other risk factors are there for lung cancer?

Answer 15

• asbestos exposure
• radiation
• genetic predisposition
• other e.g. occupation (heavy metal)

Question 16

what are the two groups that common malignant epithelial tumours of the lung split up into?
which is the worse type?

Answer 16

small cell and non small cell carcinoma

small cell carcinoma has a much worse prognosis than non-small cell carcinoma

Question 17

What is the most common form of lung cancer in non-smokers?

Answer 17

adenocarcinomas

Question 18

what are the most common types of malignant lung cancers in the mediastinum and the peripheral airways?

Answer 18

mediastinum/large airways - small cell carcinoma

peripheral arteries - adenocarcinoma

Question 19

Up to what stage are carcinomas reversible?

Answer 19

(low grade) dysplasia

Question 20

how does smoking contribute to the development of squamous cell carcinomas?

Answer 20

• the airway epithelium reacts to chronic irritation of cigarette smoke - it becomes tougher
• ciliated epithelium is delicate—–> when it is repeatedly exposed to smoke it will change into squamous epithelium
• lack of cilia = mucus is not removed from the lungs (smokers cough) and carcinogens accumulate
• the squamous cells acquire mutations so the normal pattern of growth is disrupted
• the dysplasia becomes more disrupted until it becomes a carcinoma in situ
• a further mutations will make it invasive

Question 21

What are adenocarcinomas formed from?

Answer 21

glandular epithelium

Question 22

What is an atypical adenomatous hyperplasia?

Answer 22

precursor lesion of an adenocarcinoma

proliferation of atypical cells lining the alveolar walls. Increases in size and can eventually become invasive.

Question 23

Why is the incidence of adenocarcinomas increasing?

Answer 23

they develop in the periphery-
increasing in incidence because there is deeper inhalation of cigarette smoke and because it is more common in non-smokers

Question 24

what happens during an adenocarcinoma?

Answer 24

• alveolar walls thicken and they are lined by atypical cells
• over time, some of the cells will grow large
• at some point, the cells will mutate and form enzymes that will break down the stroma
• (formation of fibrous scars) is accompanied by inflammation

NOTE: invasive tumours can metastasise and break down elastin in the BM to form fibrous stroma

Question 25

Do adenocarcinomas metastasise early or late?

Answer 25

early

Question 26

What is the worst form of lung cancer?

Answer 26

small cell carcinomas

NOTE: very rare in non-smokers

Question 27

What percentage of all lung cancers are small cell?

Answer 27

20-25%

Question 28

Why do small cell carcinomas often become necrotic?

Answer 28

they divide so fast that they often outgrow the blood supply

Question 29

Why is chemotherapy used often to target small cell carcinomas?

Answer 29

• very chemosensitive

- it has usually spread by the time it has been identified

Question 30

What is a proximal tumour most likely to be?

What physical effects can this have?

Answer 30

squamous cell carcinoma or small cell carcinoma

causes bronchial obstruction, which can lead to collapse of the distal lung and impaired drainage of the bronchus

Question 31

What is a paraneoplastic syndrome?

Answer 31

systemic effect of a tumour due to abnormal expression by tumour cells of factors (e.g. hormones) NOT normally expressed by the tissue from which the tumour arose
(i.e. a tumour expresses proteins that it would not normally express)

Question 32

What is a mesothelioma?

Answer 32

a type of cancer that develops from the thin layer of tissue that covers many of the internal organs (known as the mesothelium). The most common area affected is the lining of the lungs and chest wall.

Question 33

What is a carcinoma?

Answer 33

a cancer of the epithelial tissue