Breast cancer is the most common type of cancer among Thai women. In 2023, nearly 18,000 new cases were reported, averaging 49 diagnosed per day. Recurrence rates are significantly higher compared to other cancers. Women aged 45–55 are at the highest risk, although younger women are increasingly being diagnosed, often with the disease being more severe. Therefore, all women of reproductive age are encouraged to undergo breast cancer screening, as early detection and prompt treatment substantially increase the chances of recovery.
Breast Cancer Treatment
Surgical removal of a lump or cancerous cells (lumpectomy) or complete removal of the breast (mastectomy) remains a primary treatment method for breast cancer. These procedures are often combined with radiation therapy to eliminate residual cancer cells in the affected area, and chemotherapy, sometimes enhanced with targeted therapy drugs. Chemotherapy may be administered both before surgery to shrink the tumor and after surgery to prevent metastasis or recurrence.
Recent advancements have introduced targeted therapies, offering promising alternatives with notable benefits.
What Is Targeted Therapy?
Cancer cells exhibit unique characteristics resulting from genetic mutations, affecting their growth, immune evasion, and ability to form new blood vessels. Targeted therapy drugs are designed to specifically disrupt these mechanisms, slowing or halting cancer progression. These therapies not only improve treatment outcomes but also enhance patients’ quality of life by reducing side effects compared to traditional chemotherapy or radiation.
Targeted therapies are available in oral or injectable forms and work by:
- Inhibiting cancer cell pathways to stop growth and metastasis.
- Enhancing the immune system’s ability to identify and destroy cancer cells.
- Preventing new blood vessel formation (angiogenesis), thereby starving the tumor.
- Promoting apoptosis (natural cell death) of cancer cells.
Benefits and Side Effects of Targeted Therapy
Although targeted therapies minimize side effects, some adverse reactions still occur, such as skin issues (rashes, dryness, or nail inflammation), gastrointestinal symptoms (nausea, vomiting, or diarrhea), immune suppression, and fatigue. These effects are generally less severe than those associated with traditional chemotherapy.
Types of Breast Cancer and Targeted Therapies
1.HER2-Positive Breast Cancer
HER2-positive breast cancer accounts for approximately 20% of all breast cancer cases. The overexpression of HER2 (Human Epidermal Growth Factor Receptor 2) protein leads to rapid growth and spread of cancer cells. Targeted therapies such as Trastuzumab, Pertuzumab, and Lapatinib effectively inhibit the HER2 protein, reducing cancer cell proliferation.
Additionally, drugs like T-DM1 and Trastuzumab deruxtecan enhance the delivery of chemotherapy directly to HER2-positive cancer cells, minimizing side effects compared to traditional treatments. These therapies can be used for both early-stage and metastatic breast cancer, improving survival rates, reducing the likelihood of recurrence after surgery, and, in some cases, increasing the chances of a complete cure.
2. Hormone Receptor-Positive (HR+) and HER2-Negative Breast Cancer
This type relies on hormones like estrogen for growth. Drugs such as Palbociclib, Ribociclib, and Abemaciclib inhibit CDK4 and CDK6 proteins, which are crucial for cancer cell division. These are often combined with hormone therapy which can be performed for early and advanced stages of cancer.
3. Breast Cancer with BRCA1 or BRCA2 Mutations
For the treatment of breast cancer with BRCA1 or BRCA2 gene mutations, Olaparib and Talazoparib are used to inhibit the enzyme PARP (Poly ADP-Ribose Polymerase). This targets cancer cells, causing them to die due to their inability to repair damaged DNA. These drugs are often used in patients with advanced breast cancer with BRCA1 or BRCA2 mutations who have previously undergone chemotherapy to eliminate cancer cells..
4. Triple-Negative Breast Cancer with PD-L1 Expression
This is an immune-enhancing therapy that uses drugs such as Pembrolizumab to inhibit the PD-1 protein found on immune cells (T cells), allowing T cells to better attack and destroy cancer cells. It is often used in patients with triple-negative breast cancer that is PD-L1 expression-positive.
Hormone Therapy for Breast Cancer
Hormone therapy remains a standard treatment for HR-positive breast cancer. Drugs like Tamoxifen block estrogen receptors, while aromatase inhibitors (e.g., Anastrozole, Letrozole, and Exemestane) prevent estrogen production in postmenopausal women. Fulvestrant destroys estrogen receptors, halting tumor growth.
Personalized Breast Cancer Treatment
Treatment plans are tailored to each patient, considering cancer type, genetic profile, stage, and severity. Collaboration between oncologists and multidisciplinary teams ensures comprehensive care. Since treatment often spans a prolonged period, emotional support and active patient involvement in decision-making are crucial. This approach prioritizes the well-being and comfort of patients and their families throughout the treatment journey.
