Targeted therapy is a type of cancer treatment that uses drugs or other substances to precisely identify and attack cancer cells, usually by focusing on specific molecules involved in the growth and spread of cancer. Unlike traditional chemotherapy, which can affect both cancerous and normal cells, targeted therapy aims to interfere with cancer cell proliferation while minimizing damage to normal cells.

How Targeted Therapy Works

1. Targeting Specific Molecules: Targeted therapy drugs are designed to block specific molecules (often proteins) that are involved in cancer cell growth, division, and survival.
2. Interfering with Cancer Cell Functions: These drugs can:
   • Block signals that tell cancer cells to grow.
   • Prevent cancer cells from repairing themselves.
   • Induce cancer cell death (apoptosis).
3. Inhibiting Angiogenesis: Some targeted therapies block the growth of new blood vessels (angiogenesis) that tumors need to grow.

Types of Targeted Therapy for Lung Cancer

1. EGFR Inhibitors

• Epidermal Growth Factor Receptor (EGFR): Some lung cancers have mutations in the EGFR gene, which leads to uncontrolled cell growth.
• Drugs: Erlotinib (Tarceva), Gefitinib (Iressa), Afatinib (Gilotrif), Osimertinib (Tagrisso).

2. ALK Inhibitors

• Anaplastic Lymphoma Kinase (ALK): ALK gene rearrangements can drive cancer growth in some lung cancers.
• Drugs: Crizotinib (Xalkori), Ceritinib (Zykadia), Alectinib (Alecensa), Lorlatinib (Lorbrena).

3. ROS1 Inhibitors

• ROS1 Gene Rearrangements: Similar to ALK, ROS1 gene changes can promote cancer cell growth.
• Drugs: Crizotinib (Xalkori), Entrectinib (Rozlytrek).

4. BRAF Inhibitors

• BRAF Mutations: Mutations in the BRAF gene can be targeted.
• Drugs: Dabrafenib (Tafinlar), often combined with Trametinib (Mekinist), a MEK inhibitor.

5. VEGF Inhibitors

• Vascular Endothelial Growth Factor (VEGF): Targeting VEGF can inhibit angiogenesis.
• Drugs: Bevacizumab (Avastin).

6. MET Inhibitors

• MET Amplification: Targeting MET amplification or mutations.
• Drugs: Capmatinib (Tabrecta), Tepotinib (Tepmetko).

Usage in Lung Cancer Treatment

1. Testing for Genetic Mutations: Before starting targeted therapy, tests are performed to identify specific genetic mutations or alterations in the cancer cells. These tests include:
   • Biopsies: Tissue samples from the tumor.
   • Liquid Biopsies: Blood tests to detect circulating tumor DNA.
2. Personalized Treatment Plans: Based on the genetic profile of the tumor, a personalized treatment plan is developed using targeted therapy drugs that are most likely to be effective.
3. Combination Therapy: Targeted therapies are often used in combination with other treatments, such as chemotherapy, immunotherapy, or radiation therapy, to enhance effectiveness.
4. Managing Resistance: Cancer cells can sometimes develop resistance to targeted therapies. In such cases, alternative targeted drugs or combination strategies may be used to overcome resistance.

Benefits of Targeted Therapy

• Precision: Directly targets cancer cells with minimal impact on normal cells.
• Fewer Side Effects: Generally has fewer and less severe side effects compared to traditional chemotherapy.
• Effective for Specific Mutations: Highly effective for cancers with specific genetic mutations or alterations.

Common Side Effects

While targeted therapies tend to have fewer side effects than traditional chemotherapy, they can still cause:

• Skin Problems: Rash, dry skin.
• Diarrhea: Common with many targeted therapies.
• Liver Problems: Elevated liver enzymes.
• Fatigue: General tiredness.
• Blood Clotting Issues: Risk of bleeding or clotting.

Monitoring and Follow-up

• Regular Monitoring: Patients undergoing targeted therapy need regular monitoring to assess the effectiveness and manage any side effects.
• Adjusting Treatment: Based on response and side effects, treatments may be adjusted.

Targeted therapy represents a significant advancement in lung cancer treatment, offering a more personalized and effective approach to combating the disease.