Lung Cancers Flashcards
What is angiosarcoma?
Malignancy of vascular endothelial cells
Of skin, heart, liver, etc
UK annual incidence 1.5 cases per million
What is the prevalence of cardiovascular cancer?
Incredibly rare
What are the features of cardiac tumours?
E.g. myxoma, tumour of connective tissue
Annual incidence <1 case per million
Why are cardiac cancers so rare?
Low exposure of cells to carcinogens
Turnover rate: cardiac myocytes divide very rarely
Strong selective advantage against anything which could compromise function
Why might other organs be exposed more too carcinogens?
Lung- inhaled particles, smoking etc
Kidney/Liver - exposed to toxins
Why is the shape of cardiac cells relevant to low incidence of cancer?
Shape in cells is highly specialised
Any change will prevent the cardiovascular system from working
What is the scale of lung cancer?
3rd most common cancer in UK
~48,000 diagnoses/ year
~35,000 deaths/ year
Leading cause of cancer death
From when has lung cancer become more common?
After the 1930s
Smoking was only really popular after WW1
Who linked smoking habits with lung cancer?
Doll and Hill
What are risk factors for lung cancer?
Age, peak 75-90
Sex, M>F
Lower socioeconomic status
Smoking history
What is relevant in a smoking history?
Duration
Intensity
When stopped
What are other causes of lung cancer other than smoking?
Passive smoking
Asbestos β exposure (plumbers, ship-builders, carriage workers, carpenters, etc) β risk up to x2
Radon β e.g. silver miners in Germany late 19th century; 1950s uranium mining in Colorado
Indoor cooking fumes β wood smoke, frying fats
Chronic lung diseases (COPD, fibrosis)
Immunodeficiency
Familial/ genetic β several loci identified
What are the different types of lung cancer?
Squamous cell carcinoma
Adenocarcinoma
Large cell lung cancer
Small cell lung cancer
What are the features of squamous cell carcinomas?
Squamous cell carcinoma (~30% of cases).
β previously the most common
β originating from bronchial epithelium; centrally located
What are the features of adenocarcinomas?
Adenocarcinoma (~40%)
β most common from 1980s onwards β low tar cigarettes, inhaled more deeply / retained longer
β originating from mucus-producing glandular tissue; more peripherally-locate
What are the features of large cell lung cancer?
Large cell lung cancer (~15%)
heterogenous group, undifferentiated
What are the features of small cell lung cancer?
Small cell lung cancer (~15%)
originate from pulmonary neuroendocrine cells
highly malignant
What is NSCLC?
Non small cell lung cancer
Describe the model of lung cancer development?
Normal Epithelium Hyperplasia Squamous metaplasia Dysplasia Carcinoma in situ Invasive carcinoma
What is metaplasia?
reversible change in which one adult cell type replaced by another adult cell type; adaptive
What is dysplasia?
abnormal pattern of growth in which some of the cellular and architectural features of malignancy are present; pre-invasive stage with intact basement membrane
What are some oncogenes?
epidermal growth factor receptor (EGFR) tyrosine kinase
anaplastic lymphoma kinase (ALK) tyrosine kinase
c-ROS oncogene 1 (ROS1) receptor tyrosine kinase
BRAF (downstream cell-cycle signalling mediator)
What do genetic kinase defects cause?
Lung cancer most common in those who have never smoked
What are the key symptoms of lung cancer?
Cough Weight loss Breathlessness Fatigue Chest pain Haemoptysis Or frequently asymptomatic
Why is lung cancer often diagnosed late?
Nature of lung
Lots of space in the thoracic cavity
Does not impede on other structures quickly
Non-specific symtoms
What are features of advanced/metastatic disease?
Neurological features:
focal weakness, seizures, spinal cord compression
Bone pain
Paraneoplastic syndromes:
clubbing, hypercalaemia, hyponatraemia, Cushingβs
What is Pembertonβs sign indicative of?
Superior vena cava obstruction
Engourgement of the face due to decreased blood flow
Redness
Facial swelling
Distention of veins of neck and chest
What is Hornerβs syndrome caused be?
Apical lung tumour
Loss of sweating on side of face
Ptosis
Pupillary reconstruction
What is cachexia?
Muscle wastage
Weight loss