Lung Cancer is Responsible for More Cancer Deaths (over 20,000 per year) in Canada than any other type of Cancer

Overview:

• Significant health problem in Canada; about 90% of cases are related to smoking.
• Originates from epithelial cells that undergo metaplasia, dysplasia, and eventually become anaplastic and malignant.
• Women are more susceptible than men.
• Typically diagnosed late because the lungs have considerable reserve, allowing significant damage before symptoms appear.

Signs and Symptoms:

• Early signs: Smoker’s cough, hoarseness.
• Physical signs: Facial or arm edema if lymphatic flow is blocked (tumor near lymph nodes, especially at the lung apex).
• Localized effects: Tumors near the esophagus may cause dysphagia (difficulty swallowing).
• Respiratory issues: Atelectasis, abnormal breath sounds, shortness of breath, hemoptysis (coughing up blood).
• Pain: Due to irritation of nociceptors or invasion into adjacent tissues.
• Pleural involvement: Tumor erosion into pleura may cause pleural effusion, empyema (infection in pleural cavity), hemothorax (blood in pleural cavity), or pneumothorax (air in pleural cavity).

Hormonal Secretion & Paraneoplastic Syndromes:

• Some tumors secrete hormones mimicking endocrine disorders:
  • Excess cortisol → Cushing’s syndrome.
  • Excess antidiuretic hormone → SIADH (syndrome of inappropriate antidiuretic hormone secretion), leading to edema and hyponatremia.

Metastasis & Systemic Effects:

• Usually detected late, with metastases common in:
  • Bones (causing pain)
  • Brain (cognitive/motor deficits)
  • Liver (jaundice)
• Symptoms depend on metastatic site.

Diagnostic Tools:

• Imaging: X-rays, CT scans, MRI, PET scans.
• Biopsy: Bronchoscopy with tissue sampling for microscopic confirmation.

Treatment:

• Surgery, radiation, and chemotherapy: Often combined to remove or destroy tumor tissue.
• Photodynamic therapy: Uses laser light to target and destroy cancer cells.

Summary:  

Lung cancer presents with late symptoms due to lung reserve, often with systemic metastases. Early detection via imaging and biopsy is crucial. Treatment involves multimodal approaches, but prognosis is often guarded due to late diagnosis.