Lecture 20: Lung cancers Flashcards
Write some notes on lung cancer epidemiology;
- 5th most common
- Strong link with smoking
- Leading cause of cancer death
- Disproportionately males and maori
How strong is the link of smoking and cancer?
90% of lung cancers are in smokers, squamous and small cell lung cancer
- Linear correlation years smoking and incidence
- Other genetic and environmental factors
Describe the pathogenesis of lung cancer:
- 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
Describe the histopathological classification of primary lung cancer:
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%)
How are cancers classified?
Based on their histological appearance
Describe the histopathological classification of primary lung cancer:
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
What is the implication of histopathologic classification?
Clinical and therapeutic implications
What are some targeted therapies available in lung cancer?
Two tyrosine kinase inhibitors for non-small cell lung cancer with EGFR mutations
What are three aspects to consider in clinicopathological features of lung cancer?
Local effects
Local spread
Mediastinal spread
What are some local effects of lung cancer?
Local effects can include cough, dyspneoa, haemoptysis (bloody cough), chest pain, obstructive pneumonia
Describe considerations of local spread in lung cancer
Local spread - Pleural effusions, nerve entrapment ie horners syndrome (lung at apex impinges nerve)
Describe the considerations of mediastinal spread in lung cancer:
SVC obstruction, nerve entrapment syndromes i.e recurrent laryngeal nerve palsy
Describe how SVC obstruction can be observed?
Raising their hands above their head can bring on a red flush due to SVC obstruction to an increased VR
Describe horners syndrome as an example nerve impingement
Horners syndrome:
- Drooping eyelid (ptosis)
- Constricted pupil (miosis)
- Decreased sweating (anhydrosis)
What happens in laryngeal nerve entrapment?
Hoarse voice, can be made pronounced by speaking in a high pitch tone.
What are the features of metastatic spread in lung cancer?
Metastatic spread
- Regional lymph nodes i.e hilar
- Extranodal i.e brain, bone, liver, adrenal
What are some paraneoplastic syndromes that can occur in lung cancer?
- 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
Write some notes on SCC;
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
Where do SCC mainly arise?
Mostly arise centrally in major or segmental bronchi
What are the pathology of SCC?
- Firm grey ulcerated lesions in bronchial wall
- Extend through into adjacent lung parenchyma
- Often show necrosis, cavitation
Write some notes on lung adenocarcinoma?
- 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
What do lung adenocarcinoma architecture often reflect?
Often reflects part of resp. tract tumour arises in but subtypes of acinar, papillary, solid with mucinous formation and bronchialveolar plugging
Whats a subtype of adenocarcinoma of note?
Bronchioalveolar carcinoma
Whats of note about bronchioalveolar carcinoma?
up to 5% of all lung cancers
- Single or multiple nodules or diffuse infiltration
- Arising in existing alveolar walls
Write some notes on small cell carcinoma:
- 20% of invasive lung cancer
- Strongly linked smoking
- Highly malignant, epithelial tumour but exhibits neuroendocrine features
- Paraneoplastic syndromes common
Where are small cell carcinoma found? and whats a frequent complication?
- Arise as peri-hilar mass, often with lymph node invasion
- Frequently shows haemorrhage and necrosis on cut section
What are some other lung cancers of note and some of their features?
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
Write some notes on pulmonary metastatic disease:
- Most common neoplasm of the lung
- Typically multiple and circumscribed
- Histology that of the primary tumour
What is a tumour of the pleura? and its features:
Malignant mesothelioma
- Tumour of the mesothelial cells
- Complication of asbestos fibre exposure, long latency
What is the pathology of mesothelioma:
- Encases and compresses the lung
- Microscopically has both epithelial and sarcomatous elements
