LUNG CANCER

Types of Lung Cancer

1. Non-Small Cell Lung Cancer (NSCLC):

   • Adenocarcinoma: The most common type of lung cancer, often found in the outer parts of the lungs. It is more common in non-smokers and women.
   • Squamous Cell Carcinoma: Originates in the squamous cells lining the airways and is often linked to smoking. Typically found in the central part of the lungs.
   • Large Cell Carcinoma: A less common type that can occur in any part of the lung and is known for its rapid growth and tendency to spread.

2. Small Cell Lung Cancer (SCLC):

   • Also known as “oat cell” carcinoma, it is less common but more aggressive than NSCLC. It often starts in the central part of the lungs and spreads quickly to other parts of the body.

3. Other Types:

   • Carcinoid Tumors: Rare tumors that typically grow slowly and are different from most lung cancers. They can be classified as typical or atypical, based on their growth rate and behavior.
   • Mesothelioma: A rare cancer affecting the lining of the lungs (pleura), primarily caused by asbestos exposure.

Risk Factors

• Smoking: The leading cause of lung cancer, with a significant increase in risk associated with the amount and duration of smoking.
• Secondhand Smoke: Exposure to tobacco smoke from others can increase lung cancer risk.
• Exposure to Carcinogens: Long-term exposure to asbestos, radon, and certain chemicals (like diesel fumes or arsenic) can increase risk.
• Family History: A family history of lung cancer can increase risk, particularly in individuals with a history of smoking.
• Chronic Lung Diseases: Conditions such as chronic obstructive pulmonary disease (COPD) or pulmonary fibrosis can increase risk.
• Age: Risk increases with age, particularly in those over 65.

Symptoms

Lung cancer symptoms can vary but may include:

• Persistent Cough: A cough that does not go away or worsens over time.
• Chest Pain: Pain in the chest that may be persistent or worsen with breathing or coughing.
• Shortness of Breath: Difficulty breathing or wheezing.
• Hemoptysis: Coughing up blood or rust-colored sputum.
• Unexplained Weight Loss: Significant weight loss without an obvious cause.
• Fatigue: Persistent tiredness or weakness.
• Hoarseness: Changes in the voice or a hoarse voice.
• Recurrent Infections: Frequent respiratory infections, such as pneumonia or bronchitis.

Diagnosis

Diagnosing lung cancer involves several tests and procedures:

• Imaging Tests:

  • Chest X-Ray: Often the first test used to detect abnormal areas in the lungs.
  • CT Scan (Computed Tomography): Provides detailed cross-sectional images of the lungs to identify tumors and assess their size and spread.
  • MRI (Magnetic Resonance Imaging): Used to evaluate the spread of cancer to other parts of the body.
  • PET Scan (Positron Emission Tomography): Helps determine if cancer has spread to other organs.

• Biopsy: A sample of lung tissue is taken and examined under a microscope to confirm cancer.

  • Bronchoscopy: A flexible tube is inserted through the mouth or nose to view the airways and obtain tissue samples.
  • Needle Biopsy: A needle is inserted through the chest wall to obtain a tissue sample.
  • Thoracotomy: A surgical procedure to obtain a biopsy or remove a tumor.

• Sputum Cytology: Examination of sputum (mucus coughed up from the lungs) for cancer cells.

• Blood Tests: To assess overall health and detect abnormalities that may indicate cancer.

Staging

Lung cancer is staged based on the extent of the disease:

• Stage 0: Cancer is in the earliest stage and confined to the inner lining of the lung (carcinoma in situ).
• Stage I: Cancer is localized to the lung and has not spread to nearby lymph nodes or other organs.
• Stage II: Cancer has spread to nearby lymph nodes or tissues but not to distant organs.
• Stage III: Cancer has spread to nearby lymph nodes and possibly to nearby structures, but not to distant organs.
• Stage IV: Cancer has spread to distant organs, such as the liver, bones, or brain.

Treatment

Treatment for lung cancer depends on the type, stage, and overall health of the patient:

• Surgery:

  • Lobectomy: Removal of a lobe of the lung where the tumor is located.
  • Pneumonectomy: Removal of an entire lung.
  • Segmentectomy: Removal of a segment of the lung.

• Radiation Therapy:

  • Used to target and kill cancer cells, often used when surgery is not an option or to shrink tumors before surgery.

• Chemotherapy:

  • Uses drugs to kill cancer cells or stop them from growing. Common drugs include cisplatin, carboplatin, and paclitaxel.
  • Often used for SCLC and advanced NSCLC.

• Targeted Therapy:

  • Drugs that target specific molecules involved in cancer growth. Examples include EGFR inhibitors (e.g., erlotinib) and ALK inhibitors (e.g., crizotinib).

• Immunotherapy:

  • Uses the body’s immune system to fight cancer. Immune checkpoint inhibitors (e.g., pembrolizumab, nivolumab) are used for advanced lung cancer.

• Hormone Therapy:

  • Not typically used for lung cancer, but may be used for specific subtypes or conditions.

Prognosis

The prognosis for lung cancer varies based on factors such as the type and stage of cancer, the patient’s overall health, and response to treatment. The overall five-year survival rate for lung cancer is about 19%, but this varies widely based on stage and treatment outcomes. Early detection and treatment significantly improve the chances of a favorable outcome.

Prevention and Early Detection

• Avoid Smoking: The most effective way to reduce the risk of lung cancer.
• Avoid Secondhand Smoke: Minimize exposure to tobacco smoke from others.
• Healthy Lifestyle: Maintaining a healthy diet, regular exercise, and avoiding carcinogens can reduce risk.
• Regular Screenings: For high-risk individuals (e.g., long-term smokers or those with a family history), low-dose CT scans are recommended for early detection.

Early detection through screening and lifestyle changes, along with advances in treatment options, can significantly improve outcomes for lung cancer.