Lung Cancer: Classification, Staging, and Treatment Modalities

Lung Cancer Classification and Characteristics

Small Cell Lung Cancer (SCLC)

• Usually originates in a central location.
• High risk of lymph node metastases.
• Most patients present with metastases at diagnosis.

Non-Small Cell Lung Carcinoma (NSCLC)

• Adenocarcinoma

  • Usually peripheral.
  • More frequent in nonsmokers and women.
  • High risk of lymph node invasion and distant metastases.

• Squamous Cell Carcinoma

  • The most common of all lung cancers.
  • Normally affects the bronchi.
  • High risk of nodal involvement.

• Large Cell Carcinoma

Other Lung Tumors

• Carcinoid Tumors

Oncological Treatment for Lung Cancer

Treatment for Stages I and II Lung Cancer

Surgical Treatment (Surgery)

• Lobectomy: Excision of the lobe containing the tumor.
• Pneumonectomy: Full excision of the lung. Performed if lobectomy is insufficient due to tumor location.
• Always perform lymphadenectomy of the regional, hilar, and mediastinal nodes.

Survival Rates Post-Surgery

• Stage I: 60% to 80% at 5 years.
• Stage II: 40% to 50% at 5 years.

Adjuvant Treatment

• Radiotherapy (RT): Its use is controversial in patients with lymph node involvement (N1 or N2). While RT reduces the risk of chest recurrence, it has not consistently shown significant improvement in overall survival. RT is considered for patients at high risk of recurrence, such as those with multiple affected nodes or involved resection margins.
• Chemotherapy (QT): Not generally recommended for use in Stages I and II following surgery.

Inoperable Patients for Medical Reasons

• Radical RT is performed, often with poor outcomes.
• Survival rates are 30-60% at 2 years.

Treatment for Stage III Lung Cancer

• Chemotherapy

  • Intervention in selected cases (e.g., neoadjuvant chemoradiotherapy).
  • Aggressive treatment with a mortality rate of 5-12%.

• Radiotherapy (RT) Alone

  • Historically, very poor 5-year survival rates (around 5%).
  • No longer considered standard treatment.

• Chemotherapy (QT) + Radiotherapy (RT)

  • Survival up to 50% at 3 years.
  • Considered standard treatment for Stage III.

Radiotherapy (RTE) in Lung Cancer Treatment

Target Volume in Lung Cancer Radiotherapy

• Tumor or tumor bed with a safety margin.
• Hilar lymph node areas.
• Mediastinal lymph node areas.
• +/- Supraclavicular nodal areas.
• +/- Pleura.

Field Limits for Radiotherapy

• Upper Limit

  • Cricothyroid cleft.

• Lower Limit

  • For upper/middle lobe tumors: 2-3 cm below the carina.
  • For lower lobe tumors: Above the diaphragm.

• Horizontal Limit

  • To the outer half of the clavicles.

Side Effects on Critical Organs from Lung Cancer Radiotherapy (RTE)

• Healthy Lung

  • Pneumonitis and pulmonary fibrosis.
  • Chemotherapy for lung cancer increases the risk of pneumonitis.

• Spinal Cord

  • Radiation myelopathy.
  • In severe cases, presents a clinical picture similar to spinal shock, with loss of motor and sensory functions below the damaged area.
  • Factors influencing myelopathy onset: Radiation dose, length of irradiated spinal cord, fractionation schedule.

• Heart

  • Acute pericarditis.
  • Myocardial disease.
  • Coronary artery disease.

• Esophagus

  • From 3 Gy, acute esophagitis (marked by inflammation of the esophageal lining).
  • Dysphagia.
  • Yeast infection.
  • Ulceration and bleeding.

• Trachea

  • Tracheitis, producing an irritative dry cough.

• Brachial Plexus