Lecture 20: Lung cancers

Question 1

Write some notes on lung cancer epidemiology;

Answer 1

• 5th most common
• Strong link with smoking
• Leading cause of cancer death
• Disproportionately males and maori

Question 2

How strong is the link of smoking and cancer?

Answer 2

90% of lung cancers are in smokers, squamous and small cell lung cancer

• Linear correlation years smoking and incidence
• Other genetic and environmental factors

Question 3

Describe the pathogenesis of lung cancer:

Answer 3

• Progressive transformation of benign bronchial epithelium into neoplasm
• Stepwise accumulation of molecular changes including chromosome 3p deletions, TP53 and K-RAS mutations

i.e gradual accumulation of mutations as damage continues etc

Question 4

Describe the histopathological classification of primary lung cancer:

Answer 4

1) Small cell lung cancer (20-25%)
2) Non-small cell lung cancer (70-75%)
- Squamous cell carcinoma
- Adenocarcinoma
- Large cell carcinoma
3) Combined pattern (5-10%)

Question 5

How are cancers classified?

Answer 5

Based on their histological appearance

Question 6

Describe the histopathological classification of primary lung cancer:

Answer 6

1) Reflects cell of origin in lung i.e SSC
2) Reflects pattern of molecular changes
- K-RAS, EGFR and ALK mutations in non-small cell lung cancer
- THIS HAS IMPLICATIONS for targeted therapy

Question 7

What is the implication of histopathologic classification?

Answer 7

Clinical and therapeutic implications

Question 8

What are some targeted therapies available in lung cancer?

Answer 8

Two tyrosine kinase inhibitors for non-small cell lung cancer with EGFR mutations

Question 9

What are three aspects to consider in clinicopathological features of lung cancer?

Answer 9

Local effects
Local spread
Mediastinal spread

Question 10

What are some local effects of lung cancer?

Answer 10

Local effects can include cough, dyspneoa, haemoptysis (bloody cough), chest pain, obstructive pneumonia

Question 11

Describe considerations of local spread in lung cancer

Answer 11

Local spread - Pleural effusions, nerve entrapment ie horners syndrome (lung at apex impinges nerve)

Question 12

Describe the considerations of mediastinal spread in lung cancer:

Answer 12

SVC obstruction, nerve entrapment syndromes i.e recurrent laryngeal nerve palsy

Question 13

Describe how SVC obstruction can be observed?

Answer 13

Raising their hands above their head can bring on a red flush due to SVC obstruction to an increased VR

Question 14

Describe horners syndrome as an example nerve impingement

Answer 14

Horners syndrome:

• Drooping eyelid (ptosis)
• Constricted pupil (miosis)
• Decreased sweating (anhydrosis)

Question 15

What happens in laryngeal nerve entrapment?

Answer 15

Hoarse voice, can be made pronounced by speaking in a high pitch tone.

Question 16

What are the features of metastatic spread in lung cancer?

Answer 16

Metastatic spread

• Regional lymph nodes i.e hilar
• Extranodal i.e brain, bone, liver, adrenal

Question 17

What are some paraneoplastic syndromes that can occur in lung cancer?

Answer 17

• Small cell lung cancer i.e cushing syndrome secondary to ACTH, inappropriate ADH
• Non small cell lung cacner i.e hypercalcemia secondary to PTH-rp

Systemic features i.e weight loss

Question 18

Write some notes on SCC;

Answer 18

Squamous cell carcinoma

• 30% of all lung cancer
• Strong link with smoking b/c
• > Injury to bronchial epithelium
• > Progresses through sequence of dysplasia, carcinoma in situ, to invasive tumour

Question 19

Where do SCC mainly arise?

Answer 19

Mostly arise centrally in major or segmental bronchi

Question 20

What are the pathology of SCC?

Answer 20

• Firm grey ulcerated lesions in bronchial wall
• Extend through into adjacent lung parenchyma
• Often show necrosis, cavitation

Question 21

Write some notes on lung adenocarcinoma?

Answer 21

• 30% of invasive lung cancer
• Most common type in females
• Most common lung cancer seen in non-smokers
• Tends to arise in periphery -> later presentation
• Often in pleural fibrosis of scars

Question 22

What do lung adenocarcinoma architecture often reflect?

Answer 22

Often reflects part of resp. tract tumour arises in but subtypes of acinar, papillary, solid with mucinous formation and bronchialveolar plugging

Question 23

Whats a subtype of adenocarcinoma of note?

Answer 23

Bronchioalveolar carcinoma

Question 24

Whats of note about bronchioalveolar carcinoma?

Answer 24

up to 5% of all lung cancers

• Single or multiple nodules or diffuse infiltration
• Arising in existing alveolar walls

Question 25

Write some notes on small cell carcinoma:

Answer 25

• 20% of invasive lung cancer
• Strongly linked smoking
• Highly malignant, epithelial tumour but exhibits neuroendocrine features
• Paraneoplastic syndromes common

Question 26

Where are small cell carcinoma found? and whats a frequent complication?

Answer 26

• Arise as peri-hilar mass, often with lymph node invasion

- Frequently shows haemorrhage and necrosis on cut section

Question 27

What are some other lung cancers of note and some of their features?

Answer 27

Large cell carcinoma
- Poorly differentiated w/o features of squamous cell or adenocarcinoma; 10% of lung cancers

Carcinoid tumours

• Neuroendocrine tumours but usually ‘silent’
• Approx 2% of lung tumours; not related to smoking

Question 28

Write some notes on pulmonary metastatic disease:

Answer 28

• Most common neoplasm of the lung
• Typically multiple and circumscribed
• Histology that of the primary tumour

Question 29

What is a tumour of the pleura? and its features:

Answer 29

Malignant mesothelioma

• Tumour of the mesothelial cells
• Complication of asbestos fibre exposure, long latency

Question 30

What is the pathology of mesothelioma:

Answer 30

• Encases and compresses the lung

- Microscopically has both epithelial and sarcomatous elements