Targeted therapy is a type of cancer treatment that uses drugs designed to specifically target and attack cancer cells with minimal damage to normal cells. These therapies focus on specific molecular targets associated with cancer, such as proteins, genes, or the tissue environment that contributes to cancer growth and survival.

How Targeted Therapy Works

Targeted therapies work by interfering with specific molecules involved in cancer cell growth and progression. They can:

1. Block or Inhibit Specific Pathways: Prevent cancer cells from receiving the signals they need to grow and divide.
2. Induce Apoptosis: Trigger the self-destruction of cancer cells.
3. Inhibit Angiogenesis: Prevent the formation of new blood vessels that tumors need to grow.

Types of Targeted Therapies for Breast Cancer

1. HER2-Targeted Therapies
   • Trastuzumab (Herceptin): Binds to the HER2 receptor on cancer cells, blocking them from receiving growth signals.
   • Pertuzumab (Perjeta): Also targets the HER2 receptor but binds to a different part, enhancing the effects of trastuzumab.
   • Ado-trastuzumab emtansine (Kadcyla): Combines trastuzumab with a chemotherapy drug, delivering the chemotherapy directly to the cancer cells.
   • Sources: American Cancer Society, National Cancer Institute
2. CDK4/6 Inhibitors
   • Examples: Palbociclib (Ibrance), Ribociclib (Kisqali), Abemaciclib (Verzenio)
   • Mechanism: These drugs inhibit proteins called cyclin-dependent kinases (CDK) 4 and 6, which are involved in cell division.
   • Use: Often used in combination with hormone therapy for HR-positive, HER2-negative breast cancer.
   • Sources: BreastCancer.org, American Cancer Society
3. PI3K Inhibitors
   • Example: Alpelisib (Piqray)
   • Mechanism: Inhibits the PI3K pathway, which is involved in cell growth and survival.
   • Use: Used for HR-positive, HER2-negative breast cancer with a PIK3CA mutation.
   • Sources: National Cancer Institute, American Cancer Society
4. mTOR Inhibitors
   • Example: Everolimus (Afinitor)
   • Mechanism: Blocks the mTOR protein, which helps control cell division.
   • Use: Often used in combination with hormone therapy for advanced HR-positive, HER2-negative breast cancer.
   • Sources: American Cancer Society, BreastCancer.org
5. PARP Inhibitors
   • Examples: Olaparib (Lynparza), Talazoparib (Talzenna)
   • Mechanism: Inhibit the PARP enzyme, which helps repair DNA damage in cells.
   • Use: Used for BRCA1 or BRCA2 mutation-positive, HER2-negative breast cancer.
   • Sources: National Cancer Institute, American Cancer Society

Benefits of Targeted Therapy

• Precision: Specifically targets cancer cells, minimizing damage to normal cells.
• Fewer Side Effects: Generally causes fewer and less severe side effects compared to traditional chemotherapy.
• Improved Outcomes: Can improve survival rates and quality of life for certain types of breast cancer.

When is Targeted Therapy Used?

1. Adjuvant Therapy: After surgery to reduce the risk of cancer recurrence.
2. Neoadjuvant Therapy: Before surgery to shrink tumors.
3. Treatment for Metastatic Cancer: To control the spread and growth of advanced breast cancer.

Side Effects

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

• Fatigue
• Diarrhea
• Skin problems
• High blood pressure
• Liver problems

Summary

Targeted therapy is a critical component of breast cancer treatment, offering precision and effectiveness in managing specific types of breast cancer. The choice of targeted therapy depends on the cancer’s specific characteristics, such as HER2 status and genetic mutations.

Further Reading

• American Cancer Society: Targeted Therapy for Breast Cancer
• BreastCancer.org: Targeted Therapies
• National Cancer Institute: Targeted Cancer Therapies

These resources provide comprehensive information on the various targeted therapy options, their mechanisms, uses, and side effects.