Bronchial carcinoma

Epidemiology:

• Most common malignant tumour in the western world
• Third most common cause of death in the UK (after heart disease and pneumonia)
• 32,000 people a year die from bronchial carcinoma in the UK
• Males affected more than females (3.5:1)
• The link between bronchial carcinoma and smoking is overwhelming

Cell types:

Bronchial carcinoma is divided into 2 classes:

• Non-small cell carcinoma
• Small-cell carcinoma

Non-small cell carcinoma:

4 types:

• Squamous cell carcinoma (SCC) – accounts for 40% of all carcinomas, metastasises late
• Large-cell carcinoma – 25% of all tumours, metastasizes early
• Adenocarcinoma – 10% of all tumours, commonly metastasizes to bone and brain. Most common bronchial carcinoma associated with asbestos exposure
• Alveolar cell carcinoma – 1-2% of lung tumours, large quantities of sputum produced

Small-cell carcinoma:

• Also known as an oat-cell carcinoma
• Accounts for 20-30% of all lung tumours
• Secrete many polypeptide hormones
• Responds well to chemotherapy

Clinical features of bronchial carcinoma:

Symptom Frequency (%)

Cough 41

Chest pain 22

Cough and pain 15

Haemoptysis 7

Chest infection <5

Malaise <5

Weight loss <5

SOB <5

Hoarseness <5

Distant spread <5

Asymptomatic <5

Direct spread:

• The tumour may directly involve the pleura and ribs
• Carcinoma of the apex of the lung can erode the ribs and involve the lower part of the brachial plexus (C8, T1 and T2) causing severe pain in the shoulder and down the inner surface of the arm (Pancoast’s tumour)
• The sympathetic ganglion can also be involved, producing Horner’s syndrome
• Further extension may involve the recurrent laryngeal nerve as it passes down the aortic arch, causing unilateral vocal cord paresis with hoarseness and a bovine cough
• Bronchial carcinoma can also directly invade the phrenic nerve, causing paralysis of the diaphragm

Metastatic complications:

• Commonly metastasises to:
• Brain (causing personality change, epilepsy or a focal neurological lesion)
• Bone (severe pain and pathological fractures)
• Liver

Investigations:

CXR:

• Very valuable but very insensitive (the tumour must be >1-2cm to be visible)
• About 70% of bronchial carcinomas arise in the hilar region
• At the time of clinical presentation, the chest CXR will demonstrate >90% of carcinomas

CT scans:

• Particularly useful for identifying pathological changes in the mediastinum (such as lymphadenopathy or local spread of the tumour)
• Also good for identifying secondary spread of the carcinoma to the opposite lung by detecting masses too small to be seen on the CXR

MRI:

• Is being increasingly used for staging

Fibre-optic bronchoscopy:

• Used to obtain biopsy specimens
• If the carcinoma involves the first 2cm of either main bronchus, the tumour is inoperable
• Vocal cord paresis on the left indicates involvement of the left recurrent laryngeal nerve and inoperability

Transthoracic FNA biopsy:

• This involves the direct aspiration, through the chest wall, of peripheral lung lesions under appropriate X-ray or CT screening
• Pneumothorax occurs in 25% of patients
• Mild haemoptysis occurs in 5%

Blood tests:

FBC (to detect anaemia)

LFTs (t detect liver involvement)

Prognosis:

• Only 20% of patients are alive one year after diagnosis and only 6-8% after 5 years

Surgery:

• The only treatment of any value for non-small cell cancer of the lung is surgery
• Only 20% of all cases are suitable for resection and of these, only 25-30% survive for five years

Radiation therapy for cure:

• Useful for those patients with SCC
• It is the treatment of choice if the tumour is inoperable

Radiation pneumonitis develops in 15% of cases:

• Defined as an acute infiltrate precisely confined to the radiation area and occurring within 3 months of radiotherapy

Chemotherapy – small-cell cancer:

• Single or combination chemotherapy has resulted in a fivefold increase in survival from 2 months to 10 months
• A small number of patients enjoy several years of remission

Chemotherapy – non-small cell cancer:

• Non-small cell cancer can no longer be regarded as resistant to chemotherapy
• Response rates with single-agent treatment with newly introduced drugs exceed 20%
• Median survival can be increased to 6-12 months

Palliative treatment:

• Endobrachial irradiation
• Tracheobronchial stents
• Laser ablation via a fibre-optic bronchoscope