Clinical Aspects of Lung Cancer

Question 1

describe how common is lung cancer

Answer 1

> 45000 new cases per year (120 per day)
3rd most common cancer in the UK
90% incurable at time of diagnosis - lung cancer has no symptoms until it is too advanced
most common cause of death in men and woman in Scotland
rates of lung cancer in Scotland are among the highest in the world

Question 2

what are the usual clinical features of lung cancer

Answer 2

malignant growth
uncontrolled replication
local invasion
metastasis - secondary cancer (lymphatic spread, blood stream, serous cavities)
non-metastatic systemic effects
paraneoplastic features (molecules released from tumour that mimic natural hormones)

(deduced from its anatomical location and effects of metastases)

infected lung loses volume and gets smaller as cancer grows due to obstruction of proximal divisions of bronchial tree (all the air beyond obstruction is absorbed and lung tissue shrinks)

Question 3

describe the presentation of lung cancer

Answer 3

cough for more than 3 weeks - patient is unable to cough any sputum up (distortion of normal bronchial mucosa by tumour)

breathless for no reason (tumour in main bronchus, making it narrower)

chest infection that doesn’t clear up (tumour obstructing upper lobe bronchus)

coughing blood

unexplained weight loss

chest or shoulder pains

unexplained tiredness or lack of energy

hoarse voice (stridor)

smoker

haemoptysis - coughing up blood

Question 4

describe local invasion

Answer 4

recurrent laryngeal nerve - hoarse voice

pericardium - breathless, atrial fibrillation, pericardial effusion, oesophagus, dysphagia (indication of tumour in the oesophagus)

oesophagus

brachial plexus - pancoast tumour

pleural cavity - large volume of pleural fluid generated

superior vena cava - obstructs drainage of blood from arms and head

left pulmonary artery - no perfusion of lung, sudden death due to massive haemoptysis

chest wall - tumour invades intercostal spaces

Question 5

describe common sites of metastases

Answer 5

liver - alkaline phosphatase liver test is abnormal
brain
bone - localised pain, pathological fracture
adrenal
skin
lung
cerebral - insidious onset (weakness, visual disturbance, headaches - raised intracranial pressure), fits
cortex - epileptic fit
left adrenal gland

Question 6

describe paraneoplastic features

Answer 6

all of these features result from effects of primary tumour but not be metastatic;
finger clubbing
hypertrophic pulmonary osteoarthropathy - HPOA (elevation of peristeum away from bone surface)
weight loss
thrombophlebitis
hypercalcaemia - mimics effect of parathyroid hormone (headaches, confusion, thirst, constipation)
hyponatraemia - SIADH - mimics effect of anti diuretic hormone (confusion)
weakness - eaton lambert sydorme - mimics myaesthenia

Question 7

describe hypercalcaemia

Answer 7

stones - renal/biliary calculi
bones - bone pain
groans - abdominal pain, constipation, N+V
thrones - polyuria
psychiatric overtones - depression, anxiety, reduced GCS, coma
cardiac arrhythmias

treatment - rehydration and then IV biphosphonate

Question 8

describe hypercalcaemia

Answer 8

stones - renal/biliary calculi
bones - bone pain
groans - abdominal pain, constipation, N+V
thrones - polyuria
psychiatric overtones - depression, anxiety, reduced GCS, coma
cardiac arrhythmias

treatment - rehydration and then IV biphosphonate

Question 9

describe syndrome of inappropriate antidiuretic hormone - SIADH

Answer 9

small cell lung cancer 
results in low sodium concentration 
generalised non-specific symptoms;
nausea/vomiting 
myoclonus 
lethargy/confusion 
seizures/coma 

treatment;
treat the underlying cause
fluid restriction
demeclocycline

Question 10

describe the investigations of lung cancer

Answer 10

full blood count 
coagulation screen 
Na, K, Ca, Alk Phos
spirometry, FEV1
chest x-ray
CT scan of thorax
PET scan - assesses function rather than structure, analyses tissue uptake of radiolabelled glucose, tissues with high metabolic activity 'light up'
bronchoscopy 
endobronchial ultrasound (EBUS)

NOT sputum cytology

Question 11

explain making a tissue diagnosis of lung cancer

Answer 11

bronchoscopy - tube through nose and inspect central part of bronchial tree (tumours out in periphery of lungs), biopsies and brush cytology yield diagnosis

CT guided biopsy

lymph node aspirate

aspiration of pleural fluid

endobronchial ultrasound - bronchoscope with ultrasound tip, enabling visualisation of hilar and mediastinal structures, target and sample lymph nodes

thoracoscopy - inserted between rib spaces (lung deflated), biopsies taken from pleura

Question 12

differential diagnosis of lung cacner

Answer 12

TB
vasculitis 
pulmonary embolism
secondary cancer
lymphoma 
bronchiectasis