P03.011 Lung cancer

Lung cancer is the leading cause of cancer death worldwide, and understanding its diagnosis, management, and recent advancements is crucial for the PLAB exam. This guide provides a concise overview for medical students.

Epidemiology:

• Most common type of cancer in men and the second most common in women.
• Risk factors include smoking (primary cause), exposure to secondhand smoke, air pollution, occupational hazards (asbestos, radon), and a family history of lung cancer.

Clinical Presentation:

• Symptoms can be vague and non-specific in early stages, often leading to delayed diagnosis.
• Common presenting features include:
  • Persistent cough (productive or non-productive)
  • Hemoptysis (coughing up blood)
  • Chest pain (worsened by breathing or coughing)
  • Dyspnea (shortness of breath)
  • Weight loss
  • Fatigue
  • Recurrent pneumonia

Diagnosis:

• Chest X-ray: May show abnormalities suggestive of lung cancer, but not diagnostic.
• Low-dose CT scan: Preferred imaging modality for lung cancer screening in high-risk individuals and for further evaluation of suspicious lesions.
• Bronchoscopy: Visualization of the airways using a bronchoscope, with the option to obtain tissue samples (biopsy) for diagnosis.
• Transthoracic needle aspiration (TTNA) or core biopsy: Sampling of lung tissue with a needle guided by imaging for diagnosis.
• Mediastinoscopy or surgical lymph node biopsy: May be needed to assess lymph node involvement for staging purposes.

Staging:

• Staging determines the extent of cancer spread and guides treatment decisions.
• The TNM classification system considers tumor size (T), lymph node involvement (N), and distant metastasis (M).

Treatment:

• Curative treatment (with the intent to cure) is possible for early-stage lung cancer.
• Treatment modalities include:
  • Surgery (lobectomy, pneumonectomy): Removal of the entire lung or a lobe depending on the tumor location and size.
  • Adjuvant chemotherapy: Cytotoxic drugs administered after surgery to reduce the risk of recurrence.
  • Adjuvant radiotherapy: High-energy radiation therapy used after surgery, particularly for tumors with positive lymph node involvement.
• Palliative treatment (to manage symptoms and improve quality of life) is used for advanced or unresectable lung cancer.
  • Treatment options include palliative chemotherapy, radiotherapy, targeted therapy, and immunotherapy.

Recent Advancements:

• Targeted therapy: Drugs that target specific mutations in cancer cells, leading to improved treatment outcomes for some patients with specific mutations (e.g., EGFR mutations).
• Immunotherapy: Medications that help the immune system recognize and destroy cancer cells, showing promise in lung cancer treatment.

Points to Remember for the PLAB Exam:

• Maintain a high index of suspicion for lung cancer in smokers with persistent respiratory symptoms.
• Low-dose CT scan is the preferred tool for lung cancer screening in high-risk individuals.
• Accurate diagnosis requires tissue confirmation through biopsy.
• Staging guides treatment decisions; curative and palliative approaches exist.
• Be familiar with recent advancements in targeted therapy and immunotherapy for lung cancer.

Additional Resources:

• National Institute for Health and Care Excellence (NICE): https://www.nice.org.uk/guidance/ng122
• American Cancer Society: https://www.cancer.org/cancer/types/lung-cancer/causes-risks-prevention.html