Risk factors of lung cancer
in order:
- Smoking cigarettes
- 15-30 fold increased risk relative to non-smokers
- Radon
- 2nd most important environmental risk factor in the united states.
- 10% of lung cancer deaths in europe
- Asbestos
- Environmental tobacco exposure
- genetics
- 2 fold increased risk
- Other lung diseases
- Prior radiation
- Industrial and chemical carcinogen
- Household air pollution
Genetics of lung cancer
Li fraumeni syndrome (p53 mutations polymorphisms in cytp450)
Asbestos exposure
Causes mesothelioma from the fibres
Radiation exposures
half is radon gas found in granite stones
Lung cancer and smoking
85% is attributed to tobacco 10% of smokers get lung cancer risk is related to consumption there is no safe threshold
Trends in Smoking
Cigarette usage is going down and vaping is increasing
Lung carcinogenesis
Some abnormalities seen in lung cancer are
- atypical alveolar hyperplasia which lead to premalignant adenomas
- and bronchial metaplasia leading to dysplasia leading to carcinoma in situ
Lung cancer pathology
85% of lung cancer is is non small cell and 15% is small cell
Small cell
This is often found nearer to the hilum, this is a cancer of glandular cells so paraneoplastic syndromes can result
- 15% of lung cancers and common in smokers
- chromosome 3 short arm deletion
- can secrete ADH
- poor survival rate
highly associated with smoking metastasises really early and really quickly
Large cell carcinoma, adenocarcinoma, and squamous cell carcinoma are all non-small cell cancers.
Squamous cell carcinoma
This is a cancer of the epithelial cells of the bronchioles. They will try to form barriers which can result in keratin pearls and cell nests. This cancer has lots of keratin on top. it obstructs the bronchi and therefore presents as a cough possibly leading to brochiectasis
Large cell carcinoma
This is poorly diifferentiated and we dont know where it comes from you see pleumorphic structre and large mulptiple nucleui
Adenocarcinoma
-
frequently peripheral (on the outside of the lung)
-
often central scar from internal tensions developed
-
glandular appearance
-
may secrete mucus
-
spreads early and invades pleura
-
can look like pneumonia on xray soemtimes
Lung cancer effects
Lung cancer: Local Effects
Bronchial obstruction and pleural involvement Direct invasion
- Chest wall
- Nerves
- Mediastinum
- Intrapulmonary lymph nodes
Bronchial obstruction
Collapse endogenous lipoid pneumonia infeciton / abcess Bronchiectaiss
Lung cancer: Distant effects
distant metastases secondary to local effects non metastatic effects
Paraneoplastic Syndromes
many different catagories of paraneoplastic syndromes
Lung cancer: Investigations
- Chest X-Ray
- Sputum cytology
- Bronchoscopy
- FIne needle aspiration
- Liquid biopsy
- Advances imaging techniques
- CT scanning
- MRI, PET
- Liquid biopsy
- Testing of the blood
- This is a burgoening field in the lens of cancer
Lung cancer cytology
This is gone over in depth in the associated path tutorial.
Effects of asbestos exposure
Asbestosis
Scarring of the lungs to trap the asbestos fibres which can lead to dysplasia
Malignant mesothelioma
swallowing of mucus or gunk
Mesothelioma can look epithelioid biphasic sarmatoid