Breast cancer is a major health threat to women in Hong Kong, with over 4,100 new cases each year. The number of cases is expected to only increase. In recent years, the medical community has been actively conducting research. Taking HER2 gene-mutant breast cancer, which accounts for about 20% of breast cancer cases, as an example, multiple lines of drugs have been developed, allowing patients to receive appropriate treatment at different stages and with varying degrees of illness, thus improving their chances of survival.
For the more challenging metastatic HER2 breast cancer, the first-line targeted therapy combination of pertuzumab, trastuzumab, and chemotherapy can effectively control the disease. However, patients are likely to face drug resistance, leading to treatment failure. In such cases, doctors have traditionally switched to other chemotherapy combinations or lapatinib combined with capecitabine. In recent years, the pharmaceutical industry has developed a new generation of targeted therapy—Trastuzumab Emtansine (T-DM1). It combines targeted therapy and chemotherapy drugs, delivering the chemotherapy drugs directly to the tumor before release. In other words, it exerts the effects of both targeted therapy and chemotherapy while reducing the side effects of traditional chemotherapy, helping to maintain a better quality of life.
According to the clinical guidelines issued by the American Society of Clinical Oncology (ASCO), the recommended drug treatment options for metastatic HER2 breast cancer are as follows：
First-line treatment
- Doctors should recommend the use of Pertuzumab (Pertuzumab) plus Trastuzumab (Trastuzumab) and Paclitaxel dual-target drug combination as first-line treatment, unless the patient is not suitable for the use of paclitaxel chemotherapy drugs.
Second-line treatment
- If the patient's metastatic HER2 breast cancer worsens during or after first-line treatment, the doctor should recommend Trastuzumab Emtansine (T-DM1) as the second-line treatment.
Third-line (or later) treatment
- If the patient's metastatic HER2 breast cancer worsens during or after second-line (or subsequent) treatment, but she has never received T-DM1 treatment, the doctor should provide the patient with T-DM1 treatment.
- If the patient's metastatic HER2 breast cancer worsens during or after second-line (or subsequent) treatment, and she has already used Pertuzumab and T-DM1, the doctor should recommend that the patient use third-line or subsequent HER2 targeted therapy. Treatment options include Lapatinib with Capecitabine, or other different combinations.
There are many targeted therapeutic drugs available, which significantly increases the chance of treatment.
