LUNG CANCER Flashcards
Whats the epidemiology of lung cancer?
Over 48,000 new lung cancers are diagnosed each year in the UK
It’s the third most common malignancy in the UK and the leading cause of cancer-released death
How often is smoking implicated in lung cancer?
In 80% of cases
How is lung cancer categorised?
Small-cell lung cancer
Non-small cell lung cancer - adenocarcinoma, squamous cell carcinoma and large cell
What are the aetiological factors for lung cancer?
Tobacco smoking 80-90% of cases
Asbestos and radon gas exposure
Whats the most common type of lung cancer?
Non-small cell lung cancers account for 80-85% of lung cancers
Adenocarcinoma is the most common form (40%) and squamous cell accounts for 35%
What is adenocarcinoma of the lungs?
A cancer of the glandular cells
Which type of lung cancer is most common in non-smokers?
Adenocarcinoma (although smoking and asbestos exposure are still risk factors)
Which lung cancers tend to occur in the central parts of the lungs?
Squamous cell lung cancer
Small cell lung cancer
Which lung cancers tend to occur in the peripheries of the lungs?
Adenocarcinoma
Large cell lung carcinoma
Whats the most aggressive lung cancer type?
Small cell lung cancer - aggressive nature and early metastasis
What cell type does large cell lung cancer affect?
Epithelial cells lining the lungs
Characterised by the presence of large abnormal cells
What cell type does small cell lung cancer affect?
Kulchitsky cells which are endocrine cells - APUD cells
What are APUD cells?
An acronym for…
Amine - high amine content
Precursor Uptake - high uptake of amine precursors
Decarboxylase - high content of decarboxylase enzyme
which lung cancer is most associated with paraneoplastic syndromes?
Small cell lung cancer
Which paraneoplastic syndromes is small cell lung cancer most associated with?
Ectopic ADH secretion - hypertension, oedema, concentrated urine
Ectopic ACTH secretion - Cushing syndrome
Lambert-Eaton myasthenic syndrome
Which type of lung cancer is most likely to have cavitation lesions?
Squamous cell carcinoma
What is a bronchial adenoma?
A rare tumour that starts in the glandular tissue of bronchi
They are usually benign but they can be malignant in rare cases. Malignant bronchial adenomas are also known as carcinoid tumors and are a type of neuroendocrine tumor.
What age pt do bronchial adenomas typically affect?
Adults under 45
Which type of lung cancer is most likely to secrete beta-HCG?
Large cell lung cancer
Which type of lung cancer tends to cause tumours associated with occupation factors?
adenocarcinoma
Which lung cancer type causes excessive mucous secretion?
Adenocarcinoma
What is radon?
A colourless, odourless gas which is a natural breakdown product of uranium found in the soil
Which gene mutations are associated with lung cancer?
Epidermal growth factor receptor gene - EGFR
TP53
KRAS
Anaplastic lymphoma kinase gene - ALK
ROS1 gene
BRAF gene
Neurotrophic tyrosine receptor kinase gene - NTRK
Mesenchymal-epithelial transition gene - MET
RET gene
Where does lung cancer typically metastasise to?
Mediastinum
Hilar lymph nodes
Lung pleura
Heart
Breasts
Liver
Adrenal glands
Brain
Bones
Why does small cell carcinoma have a poor prognosis?
Rapid growth
High propensity + rapid ability to metastasise
Often resistant to conventional cancer treatments
Late diagnosis which limits treatment options
How do we stage small cell carcinomas?
Limited - if cancer is confined to one lung and may have spread to lymph nodes on the same side
Extensive - if spread beyond 1 lung
How do we stage non-small cell carcinoma?
TNM staging
Which lung tumours can form Pancoast tumours?
Non-small cell lung cancers - squamous cell is most common. Adenocarcinomas and large cell carcinomas can cause them but it’s less common
(Small cell lung cancer rarely causes them as it tends to grow centrally in the lung)
What are Pancoast tumours?
Aka a superior sulcus tumour
A tumour arising in the very apex of the lungs and invading the surrounding tissue and chest wall - must cause characteristic symptoms to be considered a Pancoast tumour e.g. shoulder pain, arm weakness, arm numbness, and Horner’s syndrome
What can Pancoast tumours compress and damage?
Thoracic inlet and thoracic outlet obstructions
Brachial plexus
Cervical sympathetic nerve
What causes Horner syndrome?t
Compression of cervical sympathetic nerves typically by a Pancoast tumour
What are the symptoms of Horner syndrome?
Ptosis
Myosis
Anhydrosis
Enopthalmosis (sunken eye)
Which paraneoplastic syndromes are most associated with squamous cell lung cancer?
Hypercalcaemia (parathyroid hormone-related protein produced from tumour cells). In 50% of pt
Others - clubbing, hypertrophic pulmonary osteoarthropathy and hyperthyroidism (due to ectopic TSH)
Which paraneoplastic syndromes are most associated with large cell lung cancer?
Really rare
Hypertrophic pulmonary osteoarthropathy
Neuromyopathy
Lambert-Eaton syndrome
May secrete beta hCG
Which paraneoplastic syndromes are most associated with adenocarcinoma?
Gynaecomastia (related to secretion of HCG or alpha-fetoprotein or estrogen-like substances by tumour)
Hypertrophic pulmonary osteoarthropathy
What is SIADH?
Syndrome of inappropriate anti diuretic hormone
Hyponatraemia secondary to the dilution all effects of excessive water retention by the kidneys due to ezxcess ADH
How does small cell lung cancer cause Cushing syndrome?
10-15% of SCLC patients have tumours which produced ACTH or CRH which stimulates the adrenal glands to produce more cortisol than the body needs = Cushings
How do small cell lung cancers cause lambert-Eaton syndrome?
Autoimmune disorder
Tumour cells produce a protein called voltage-gated calcium channel which is similar in structure to presynaptic voltage gated calcium channels found in nerve cells in PNS. The immune system produces antibodies against it which can cross-react with calcium channels on nerve cells leading to impaired nerve conduction and muscle weakness
What causes hypertrophic pulmonary osteoarthropathy?
Tumour cells release certain hormones and cytokines such as vascular endothelial growth factor which lead to inflammation and abnormal bone growth
Associated with lung cancer but may also be caused by COPD, cystic fibrosis and other lung disorders
What are symptoms of SIADH?
Nausea and vomiting
Headaches
Confusion and disorientation particularly in elderly
Seizures
Muscle weakness or cramps
Fatigue
What are symptoms of hypercalcaemia?
Stones - renal calculi
Bones - bone pain
Groans - abdominal pain
Thrones - polyuria
Psychiatric moans - altered mental status
What are the 2 mechanisms by which lung cancers may cause hypercalcaemia?
Bony metastasis
Tumour secretion of parathyroid hormone-related protein
What are symptoms of Cushing’s syndrome?
Fatigue
Depression
Weight gain
Easy bruising
Amenorrhoea and reduced libido
Striae
Acne
Moon facies
Buffalo hump
Hypertension
Proximal muscle weakness
Hyperpigmentation
What are symptoms of lambert-Eaton syndrome?
Repeated muscle contractions lead to increased muscle strength
Limb-girdle weakness
Hyporeflexia
Autonomic symptoms - dry mouth, impotence, difficulty micturition
Opthalmoplegia and ptosis less common
What are symptoms of hypertrophic pulmonary osteoarthropathy?
Joint stiffness
Severe pain in wrists and ankle
Sometimes gynaecomastia
Digital clubbing
On x-ray - proliferative periostitis at the ends of the long bones which have an ‘onion skin’ appearance
What can Pancoast tumours cause?
Horners syndrome
Pain in shoulder that radiates into arm and hand
Atrophy of muscles of upper limb
Oedema of upper limb
Whats the most common lung cancer to cause superior vena cava obstruction?
Small cell lung cancer
What are the features of SVC obstruction?
Dyspnoea
Swelling of face, neck and arms (conjunctival and periorbital oedema may be seen)
Headaches that are worse in the morning
Visual disturbance
Pulseless jugular venous distension