Lung cancer Flashcards
How common is lung cancer?
Very common, second most common cancer in the UK
Risk factors for lung cancer
- Smoking (90%)
- Passive smoking
- Asbestos
- Chromium
- Arsenic
- Iron oxides
- Radiation (radon gas)
Lung cancer histology
- Non-small cell lung cancer
- Squamous cell carcinoma (35%)
- Adenocarcinoma (25%)
- Large cell (10%)
- Adenocarcinoma in situ (~1%)
- Small cell lung cancer
What can small cell lung cancer cause?
As small cell lung cancer arises from endocrine cells it contains neurosecretory granules that can release neuroendocrine hormones resulting in paraneoplastic syndromes (eg production of ACTH, Cushing’s syndrome).
Symptoms of lung cancer
- Cough (80%)
- Haemoptysis (70%)
- Dyspnoea (60%)
- Chest pain (40%)
- Recurrent or slowly resolving pneumonia
- Lethargy
- Anorexia
- Weight loss
General signs of lung cancer
- Cachexia
- Anaemia
- Clubbing
- HPOA (hypertrophic pulmonary osteoarthropathy, causing wrist pain)
- Supraclavicular or axillary lymph nodes
Chest signs for lung cancer
- None or
- Consolidation
- Collapse
- Pleural effusion
Signs of metastatic disese
- Bone tenderness
- Hepatomegaly
- Confusion
- Focal CNS signs
- Proximal myopathy
- Peripheral neuropahty
What ia the first line investigation in suspected lung cancer and what findings would be suspicious?
Chest X-ray
- Hilar enlargement
- “Peripheral opacity” – a visible lesion in the lung field
- Pleural effusion – usually unilateral in cancer
- Collapse
Further investigations for lung cancer:
- Staging CT scan of chest, abdomen and pelvis to establish the stage and check for lymph node involvement and metastasis. This should be contrast enhanced.
- PET-CT (positron emission tomography) scans involve injecting a radioactive tracer (usually attached to glucose molecules) and taking images using a combination of a CT scanner and a gamma ray detector to visualise how metabolically active various tissues are. They are useful in identifying areas that the cancer has spread to by showing areas of increased metabolic activity suggestive of cancer.
- Bronchoscopy with endobronchial ultrasound (EBUS) involves endoscopy of the airways (bronchi) with ultrasound on the end of the scope. This allows for detailed assessment of the tumour and ultrasound guided biopsy.
- Histological diagnosis to check the type of cells in the cancer requires a biopsy. This can be either by bronchoscopy or percutaneously (through the skin).
- Which lung cancer patients would recieve surgery as first line currative treatment?
- What does this involve?
- What other treaments may be offered?
- Non-small cell lung cancer and disease isolated to a single area
- Lobectomy (removing the lung lobe containing the tumour) is first line. Segmentectomy or wedge resection (taking a segment or wedge of lung to remove the tumour) is also an option.
- Radiotherapy can also be curative in non-small cell lung cancer when early enough. Adjuvant chemotherapy in certain patients to improve outcomes.
Treatment for small cell lung cancer
Chemotherapy and radiotherapy - prognosis is generally worse for small cell lung cancer than non-small cell lung cancer
What could be used as part of a palliative treatment to relieve bronchial obstruction caused by lung cancer?
Endobronchial treatment with stents or debulking
How could a lung cancer present with a hoarse voice?
Recurrent laryngeal nerve palsy is caused by the cancer pressing on or affecting the recurrent laryngeal nerve as it passes through the mediastinum.
What nerve palsy could occur in lung cancer causing shortness of breath?
Phrenic nerve palsy due to nerve compression causes diaphragm weakness and presents as shortness of breath.
Cause and symptoms of superior vena cava obstruction
Superior vena cava obstruction is a complication of lung cancer. It is caused by direct compression of the tumour on the superior vena cava.
It presents with facial swelling, difficulty breathing and distended veins in the neck and upper chest.
“Pemberton’s sign” is where raising the hands over the head causes facial congestion and cyanosis. This is a medical emergency.
What is Horner’s syndrome?
Horner’s syndrome is a triad of partial ptosis, anhidrosis and miosis.
It is caused by a Pancoast’s tumour (tumour in the pulmonary apex) pressing on the sympathetic ganglion.
How could lung cancer present with hyponatraemia?
Syndrome of inappropriate ADH (SIADH) caused by ectopic ADH secretion by a small cell lung cancer
How can lung cancer present with Cushing’s syndrome?
Cushing’s syndrome can be caused by ectopic ACTH secretion by a small cell lung cancer
How can lung cancer present with hypercalcaemia?
Hypercalcaemia caused by ectopic parathyroid hormone from a squamous cell carcinoma
How does lung cancer cause limbic encephalitis and what are the symptoms?
This is a paraneoplastic syndrome where the small cell lung cancer causes the immune system to make antibodies to tissues in the brain, specifically the limbic system, causing inflammation in these areas. It is associated with anti-Hu antibodies.
This causes symptoms such as short term memory impairment, hallucinations, confusion and seizures.
What causes Lambert-Eaton Myasthenic Syndrome?
Lambert-Eaton myasthenic syndrome is a result of antibodies produced by the immune system against small cell lung cancer cells. These antibodies also target and damage voltage-gated calcium channels sited on the presynaptic terminals in motor neurones.
Symptoms of Lambert-Eaton Myasthenic Syndrome
Weakness, particularly in the proximal muscles but can also affect intraocular muscles causing diplopia, levator muscles in the eyelid causing ptosis and pharyngeal muscles causing slurred speech and dysphagia.
How do the symptoms of Lambert-Eaton myasthenic syndrome differ to those of myasthenia gravis?
The symptoms tend to be more insidious and less pronounced in Lambert-Eaton syndrome.
