Aetiology and Pathology of Lung Cancer

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Questions and Answers

What percentage of lung cancer cases in the UK is cigarette smoking thought to directly cause?

95%

85% (correct)

70%

50%

Which cell type comprises the largest percentage of lung cancers?

Large-cell carcinoma

Squamous carcinoma

Small-cell carcinoma

Adenocarcinoma (correct)

Which demographic group has seen a rising incidence of lung cancer deaths that surpasses that of men in some Nordic countries?

Elderly men

Urban dwellers

Children

Women (correct)

What is the primary pathway for the spread of lung cancer to local lymph nodes?

Lymphatic spread Signup and view all the answers

Which of the following represents a typical symptom of a peripheral bronchial tumour?

Delayed diagnosis due to late symptoms Signup and view all the answers

What environmental factor has been suggested to contribute to the higher incidence of lung cancer in urban areas compared to rural areas?

Increased atmospheric pollution Signup and view all the answers

How many new cases of lung cancer are estimated worldwide each year?

1.8 million Signup and view all the answers

What condition is particularly characteristic of small cell lung cancers?

Widespread metastatic deposits from small primary tumours Signup and view all the answers

Which industrial exposure is NOT associated with an increased risk of lung cancer?

Silica Signup and view all the answers

What is the most common early symptom of lung cancer?

Persistent cough Signup and view all the answers

What symptom should always raise suspicion of lung cancer in smokers?

Change in character of cough Signup and view all the answers

Which type of obstruction may lead to a unilateral wheeze that does not clear with coughing?

Partial bronchial obstruction Signup and view all the answers

What complication may occur if central tumours invade large vessels?

Sudden massive haemoptysis Signup and view all the answers

What does mediastinal spread of lung cancer potentially involve that may cause vocal cord paralysis?

Involvement of the left recurrent laryngeal nerve Signup and view all the answers

What is a common sign of hypertrophic pulmonary osteoarthropathy (HPOA) associated with lung cancer?

Painful periostitis of long bones Signup and view all the answers

Which syndrome is usually associated with small cell lung cancer and involves inappropriate ADH secretion?

Syndrome of inappropriate antidiuretic hormone secretion (SIADH) Signup and view all the answers

Which symptom indicates possible late-stage lung cancer involving large pleural effusion or respiratory nerve compression?

Breathlessness Signup and view all the answers

What does digital clubbing often indicate in relation to lung conditions?

Lung cancer Signup and view all the answers

What condition may exhibit symptoms like lassitude, anorexia, and weight loss as indicators of metastatic spread?

Metastatic lung cancer Signup and view all the answers

What neurological condition associated with lung cancer can cause leg weakness and loss of bladder control?

Myelopathy Signup and view all the answers

Study Notes

Aetiology of Lung Cancer

Smoking: Cigarette smoking is the leading cause, responsible for at least 85% of UK cases. Risk increases with amount smoked and tar content.
Passive Smoking: Contributing to 5% of lung cancer deaths, although quantification is harder.
Urban vs. Rural: Slightly higher incidence in urban areas, potentially linked to atmospheric pollution (including tobacco smoke).
Occupational Exposure: Certain industrial materials, like asbestos, arsenicals, and beryllium compounds, are associated with lung cancer.

Lung Cancer Pathology

Origin: Arises from the bronchial epithelium or mucous glands.
Common Cell Types:
- Adenocarcinoma (35-40%)
- Squamous cell carcinoma (25-30%)
- Small cell carcinoma (15%)
- Large cell carcinoma (10-15%)
Location and Symptoms:
- Central (large bronchus) tumors present early with symptoms.
- Peripheral (small bronchus) tumors can grow large before detection. Peripheral squamous cell tumours have a high chance of developing necrosis and cavitation, possibly mimicking lung abscess on X-ray.

Epidemiology Summary

Global Incidence: 1.8 million new cases annually worldwide.
Gender Differences: Most common in men, but female rates are rising, surpassing male rates in some Nordic countries and replacing breast cancer deaths in others.
Historical Trends: More than a threefold increase in deaths since 1950.
Metastasis at Diagnosis: Over 50% of cases have metastatic disease at diagnosis.

Lung Cancer Spread

Local Spread: Can involve pleura, chest wall, intercostal nerves, and/or brachial plexus, causing pain. Lymphatic spread (mediastinal and supraclavicular lymph nodes) often occurs before diagnosis.
Metastatic Spread: Most common sites: liver, bone, brain, adrenals, and skin. Small primary tumors can still result in widespread metastases, especially in small cell lung cancer.

Clinical Features

Cough: A common early symptom, often dry but may become productive of sputum with secondary infection. Change in smoker's cough should raise suspicion.
Haemoptysis: Common, especially with central tumors but also with infection. Investigation is essential in smokers.
Bronchial Obstruction: Partially or completely blocking airflow. Symptoms include collapse of lung, wheeze, pneumonia, and lung abscess (especially in smokers).
Breathlessness: Caused by lung collapse, pneumonia, pleural effusion, or phrenic nerve compression.
Pain and Nerve Entrapment (HIP): Pleural pain, intercostal nerve pain, Horner syndrome (eye symptoms), and Pancoast syndrome (arm pain).
Mediastinal Spread (SPRED): Superior vena cava syndrome, lymph node involvement, pericarditis, recurrent left lymph node involvement, and esophageal dysphagia.
Supraclavicular Lymph Nodes: Palpable or detectable with ultrasound. Needle aspirate useful for diagnosis.

Metastatic Spread Clinical Features

Systemic symptoms: focal neurological symptoms, seizures, personality changes, jaundice, bone pain, skin nodules, lassitude, anorexia, weight loss.
Finger clubbing and hypertrophic pulmonary osteoarthropathy (HPOA): Can indicate lung cancer spread or tumour presence.
- Distal limb pain.
- Soft tissue growth on the fingertips.
- Possible subperiosteal new bone formation.

Non-metastatic extrapulmonary effects

Endocrine: SIADH (inappropriate ADH secretion), Cushing syndrome (ectopic ACTH), hypercalcemia (parathyroid hormone-related peptides), carcinoid syndrome, gynecomastia.
Neurological: Polyneuropathy, myelopathy, cerebellar degeneration, myasthenia (Lambert-Eaton syndrome).
Other: Digital clubbing, hypertrophic pulmonary osteoarthropathy, nephrotic syndrome, polymyositis/dermatomyositis, eosinophilia.

Noteworthy associations

Small cell lung cancer is commonly associated with SIADH and ectopic ACTH.
Hypercalcemia may point to malignant bone destruction or tumor-produced hormonal peptides.
Neurological syndromes can be associated with all lung cancer types.

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Description

This quiz covers the causes and pathology of lung cancer, focusing on key risk factors such as smoking and occupational exposure. It also addresses the different cell types and locations of lung tumors, along with symptoms associated with each type. Enhance your understanding of lung cancer's complexities through this informative quiz.