Resp19 - Lung Cancer

Question 1

Lung Cancer

Prevalence and Prognosis
Risk Factors
Common Presentations
Referral Criteria

Answer 1

1. ) Prevalence and Prognosis
   - most common type of cancer in men, prevalent in low socio-economic groups due to ↑smoking rates
   - no screening program in the UK
   - poor prognosis: 5% 5yr survival rate, majority present already at stage 3/4 disease, unfortunately, it is the most common cause of death from cancer in the UK
2. ) Risk Factors
   - smoking is the most significant cause of lung cancer
   - advanced age, family history, diet
   - exposure to carcinogens e.g. asbestos, radon and other occupational carcinogens
   - interstitial lung disease e.g. IPF
3. ) Common Presentations
   - chest signs: persistent cough (>3wks), haemoptysis, dyspnoea, wheeze, chest pain, recurrent pneumonia
   - fatigue, poor appetite, weight loss
   - hoarseness of voice, signs of SVCO syndrome
   - examination: fixed monophonic wheeze, clubbing lymphadenopathy (supraclavicular, cervical)
4. ) Referral Criteria - CXR w/in 2wks in >40s with:
   - chest signs of lung cancer
   - recurrent or persistent chest infections
   - finger clubbing, Lymphadenopathy (supraclavicular or persistent abnormal cervical nodes)
   - thrombocytosis (raised platelet count)

Question 2

Types of Lung Cancer

Small Cell Lung Cancer (SCLC)
Non-Small Cell Carcinoma (NSCLC)
Squamous Cell Carcinoma (SCC)
Adenocarcinoma
Other Non-Small Cell Lung Cancers 
Mesothelioma

Answer 2

1. ) Small Cell Lung Cancer (15%) - very aggressive so often caught in late-stage (already metastasised)
   - commonly spreads to the bone, brain, and liver
   - often caused by smoking, more common in females
   - cells contain neurosecretory granules that can release neuroendocrine hormones –> paraneoplastic syndromes

2.) Non-Small Cell Carcinoma (85%) - less invasive so less likely to metastasize, grows more in the peripheries whilst SCLC grow more centrally

3. ) Squamous Cell Carcinoma (40%) - NSCLC
   - affects the cells lining the airways (central disease)
   - highest link to smoking of all NSCLCs
4. ) Adenocarcinoma - 35% - NSCLC
   - glandular cells secreting mucin/mucous
   - most common type in non-smokers and most common type of lung cancer in general
   - prognosis is 50% survival at 5 years
5. ) Other Non-Small Cell Lung Cancers
   - large cell carcinoma (5%): very large and round cells
   - carcinoid tumours (5%): tumour of neuroendocrine cells, has no link to smoking
6. ) Mesothelioma - malignancy affecting mesothelial cells of the pleura caused by asbestos exposure
   - can be up to 45yrs between exposure to asbestos
   - very poor prognosis, chemo is essentially palliative
   - not a form of lung cancer

Question 3

Extrapulmonary Manifestations of Lung Cancer

Superior Vena Cava Obstruction
Nerve Palsies
Paraneoplastic Syndromes of SCLC
Paraneoplastic Syndromes of Non-SCLC

Answer 3

1. ) SVC Obstruction - compression of the tumour on the superior vena cava, this is a oncological emergency
   - sx: SOB, facial swelling, headache (worse in morning), distended neck and upper chest veins in the
   - Pemberton’s sign: raising the hands over the head causes facial congestion and cyanosis
   - Mx: endovascular stenting for symptom relief, radical chemo/radiotherapy can be used instead
2. ) Nerve Palsies - compression of nerves causes:
   - recurrent laryngeal nerve: hoarse voice
   - phrenic nerve: elevated/weak diaphragm –> SOB
   - Horner’s syndrome: Pancoast tumour (tumour in the pulmonary apex) presses on sympathetic ganglion
   - brachial plexus: arm and hand weakness/pain
   - pancoast tumour is a SCC often found in the right apex of the lung that can cause all of the above as well as some paraneoplastic syndromes aswell
3. ) Paraneoplastic Syndromes of SCLC
   - SIADH: ectopic ADH, presents w/ hyponatraemia
   - Cushing’s syndrome: ectopic ACTH
   - Lambert-Eaton Syndrome: antibodies against presynaptic VGCa channels in PNS leads myasthenia gravis type sx in the lower limbs (rather than face)
   - limbic encephalitis: (anti-Hu) antibodies to tissues in the brain by SCLC, causes memory impairment, hallucinations, confusion and seizures
4. ) Paraneoplastic Syndromes of Non-SCLC
   - squamous cell carcinoma: hypercalcemia (PTHrP), hyperthyroidism (ectopic TSH), finger clubbing
   - adenocarcinoma: gynaecomastia (↑ß-hCG /oestro)

Question 4

Investigations in Lung Cancer

Initial Investigations
Biopsy
Staging Imaging
TNM Staging

Answer 4

1. ) Initial Investigations
   - CXR: hilar enlargement, peripheral opacity, pleural effusion (often unilateral), collapse, however in 10% of patients w/ lung cancer, the CXR is normal
   - bloods: FBC (↑platelets)
   - WHO performance status: baseline level of fitness:
   0: fully active, 1: light activity, 2: all selfcare, 3: limited selfcare, 4: bed-bound, 5: dead
2. ) Biopsy - required for histological diagnosis
   - bronchoscopy with endobronchial ultrasound (EBUS): detailed assessment of tumour and US-guided biopsy
   - bronchoalveolar lavage/bronchial washing (aspirate the contents of the lung for flow cytometry)
   - CT-guided to reach difficult areas of the lung
   - alternatively, a percutatneous biopsy can be used
   - thoracoscopy is used if pleural effusion is present, it is much better to for malignant mesotheliomas
   - transthoracic needle biopsies have a 10% risk of the pneumothorax
3. ) Staging Imaging
   - CT-CAP w/ contrast (gold): assess TNM staging, lymph node involvement and presence of metastases
   - PET-CT: only used in Non-SCLC to establish eligibility for curative treatment, has better sensitivity for local and distant mets spread in Non-SCLC
4. ) TNM Staging - helps determine treatment options
   - all metastases are bad, suggests stage 4 lung cancer
   - T >5cm is bad as it is not surgically resectable
   - <5cm w/o lymph node involvement is curable
   - radiotherapy is only offered for peripheral cancers as it can damage surrounding structures

Question 5

Management of Lung Cancer

Non-Small Cell Lung Cancer
Lung Cancer Surgery
Small Cell Lung Cancer

Answer 5

1. ) Non-Small Cell Lung Cancer
   - only 20% are suitable for surgery, contraindications: any metastases, vocal cord paralysis, SVCO, malignant pleural effusion, a tumour near the hilum, FEV1 <1.5L
   - radiotherapy only (can be curative or palliative) as NSCLC has a poor response to chemotherapy
2. ) Lung Cancer Surgery
   - removal options include segmentectomy or wedge resection (a portion of one lobe), lobectomy (entire lobe), pneumonectomy (removing an entire lung)
   - types: video-assisted thoracoscopic surgery (keyhole), and robotic, thoracotomy (open surgery)
   - thoracotomy incisions: posterolateral (most common), anterolateral, axillary
   - chest drain is left in after thoracic surgery to allow drainage of air and fluid to exit the thoracic cavity and the lungs to expand
3. ) Small Cell Lung Cancer
   - usually metastatic disease by the time of diagnosis
   - most patients with limited disease receive a combination of chemotherapy and radiotherapy
   - extensive disease: palliative chemotherapy
   - patients with very early-stage disease (T1-2a, N0, M0) are now considered for surgery

Question 6

complications of lung cancer

Answer 6

metastatic spinal cord compression
hypercalcaemia, Ca >2+, can also give duiretics (furosemide
SVCO
SIADH
brain metastases - cannot drive