Malignant Lung Pathology Flashcards
Define a malignant lung tumour
Tumours within the lung that possess potentially lethal abnormal characteristic that enables them to invade and metastasise/spread to other tissues.
What are the two types of malignant lung tumours?
1ary and 2ary
What are 1ary malignant lung tumours?
Originate in the lung
What is the most common (>90%) type of 1ary malignant lung tumour?
Carcinomas
How are carcinomas broadly classified?
Based on light microscopy (histology);
1) Small cell carcinoma (15-20%)
2) Non-small cell carcinoma (80-85%)
Non-small cell carcinomas can be further divided into what?
Based on histology;
1) Squamous cell carcinoma (20-30%)
2) Adenocarcinoma (30-40%)
3) Large cell undifferentiated carcinoma (10-15%)
What 2 features do SCCs show?
areas of keratinisation and/or intercellular bridges
What 2 features do adenocarcinomas show?
Produce mucin and/or show areas of gland formation
Which tumours show areas of keratinisation?
SCCs
Which tumours show areas of gland formation?
Adenocarcinoma
Aside from SCCs, adenocarcinomas and large cell undifferentiated carcinomas, what are 3 other 1ary malignant lung tumours (less common)?
- Carcinoid tumours
- Malignant mesenchymal tumours
- Primary lung lymphomas
Survival of carcinoid tumours?
Low grade malignant tumours, better survival
Who are primary lung lymphomas more commonly seen in?
can be seen in HIV/AIDS patients
What is the most common type of malignant mesenchymal tumour?
synovial sarcoma
What are 2ary lung tumours?
Tumours that have arisen in other areas of body and metastasised to the lungs.
Are 1ary or 2ary lung tumours more common?
2ary
How do 2ary lung tumours typically present?
As multiple discrete nodules, can also be solitary
What is the most common form tumour that can metastasise to cause a 2ary lung tumour?
Most common are carcinomas from various sites eg. Breast, GI tract, Kidney
What other tumours can metastasise to cause a 2ary lung tumour?
Sarcomas
Melanomas
Lymphomas
Epidemiology of Lung Cancer
Most common cause of cancer death in the UK and worldwide.
In the UK around 45 000 new cases are diagnosed each year and > 30 000 deaths/year.
M > F, only slight
Major public health problem.
Age usually between 40 and 70 yrs, rare in younger individuals
What has the rise in the incidence of Lung Cancer over the last century closely paralleled?
Cigarette smoking
What is the 5 year survival rate of lung cancer?
5-10%
Aetiology of lung cancer?
- Tobacco smoking
- Occupational/Industrial hazards, eg Asbestos, uranium, arsenic, nickel
- Radiation – mines in which there is radon
Can ALSO be predisposed by;
- Lung fibrosis
- Genetic mutations
Which genetic mutations can predispose to lung cancer? Who are these seen in?
EGFR, KRAS, ALK etc
Usually seen lung cancers in non smokers
Mutations in which genes drive lung cancer?
Mutations in key genes regulating cell proliferation, DNA repair and apoptosis
How can cigarette smoke lead to SCC?
Squamous metaplasia –> dysplasia –> carcinoma in-situ –> frank squamous carcinoma
What is squamous metaplasia?
A pre-neoplastic change of the bronchial epithelium observed in the lungs in response to toxic injury induced by cigarette smoke
What does squamous epithelium replace in squamous metaplasia?
Columnar epithelium
What is dysplasia?
A broad term that refers to the abnormal development of cells within tissues or organ
What is carcinoma in situ?
Carcinoma in situ refers to cancer in which abnormal cells have not spread beyond where they first formed.
How many pack years is 40 cigarettes per day for 6 months?
1
Where do 2/3rd of world smokers reside?
China
What is the latent period between exposure to asbestos and development of carcinoma?
20 years
The risk of carcinoma after asbestos exposure increases 20-100 fold if combined with what?
Cigarette smoking
What other respiratory illnesses is asbestos associated with?
lung fibrosis and mesothelioma
What is mesothelioma?
malignant tumour of the pleura
What is a common feature of brain metastases?
Epilepsy/seizures
How do bone metastases affect calcium levels?
Increased calcium levels - bone metastases cause an imbalance between bone formation and bone resorption, resulting in the release of excess calcium into the blood.
How do bone metastases affect fragility of bone?
Increased risk of pain and fracture
Why can lung cancer present with haemoptysis?
Central tumours arising in proximal airways can ulcerate and bleed
Why can lung cancer present with breathlessness or features of pneumonia?
Tumour obstructing airways with distal collapse or consolidation
Lung tumours can infiltrate into adjacent structures. What are the features if it infiltrates;
a) pleura
b) chest wall/ribs
c) recurrent laryngeal nerve
d) sympathetic chain
e) oesophagus
a) pleural effusion presenting as breathlessness
b) pain
c) hoarseness
d) Horner’s syndrome
e) dysphagia
What are common sites of metastases of lung tumours?
lymph nodes, pleura liver, bone, adrenal, brain
How would metastases to bone present?
Fracture
How would metastases to lymph nodes present?
Lumps in neck
Non specific features of lung cancer?
- Usually metabolic effects
- Weight loss, lethargy
- Electrolytic disturbances
- Finger clubbing
What electrolyte disturbances are seen in small cell carcinoma?
Hyponatraemia or hypokalaemia
What electrolyte disturbances are seen in SCC?
Hypercalcaemia
What is lymphangitis carcinomatosa?
Lymphatics within the lung are diffusely involved by tumour.
If patients are diagnosed with early stage (disease limited to lung or extension into local nodes), what management can they be offered?
Surgery or radical radiotherapy - almost curative
Patients must be fit for surgery
What is Personalised/Precision Medicine?
Selection of patients for a specific treatment based on the presence of specific biomarkers which indicate sensitivity to corresponding targeted therapies and /or lower toxicity risk, such patients will have the greatest chance of deriving benefit from the treatments.
Recent Advances in Treatment of Lung Cancer with advanced disease :
Targeted/tailored therapy
Based on tumour genomics, driver mutations eg EGFR mutations, ALK re-arrangements, ROS 1, BRAF etc
Immune checkpoint inhibitors eg PD-L1
Which immune checkpoint can be looked for in personalised treatment of lung cancer?
PD-L1
