A groundbreaking approach to treating late-stage breast cancer has emerged, utilizing a new generation of targeted therapy known as Antibody-Drug Conjugates (ADC). This treatment has shown remarkable results in patients who have exhausted other options. A notable case is that of a 55-year-old woman, referred to as Mrs. Dung, who was diagnosed with stage 4 breast cancer with pleural effusion.

Mrs. Dung's treatment involved a new ADC that combines a targeted antibody against the HER2 receptor with a potent cancer-killing agent. According to Dr. Nguyen Tuong Van from the Oncology Department at Tam Anh General Hospital in Ho Chi Minh City, the mechanism of this drug functions like a "smart bomb." The antibody first locates and binds to the HER2 receptors on the surface of cancer cells. Once inside the cell, it releases a powerful chemical that destroys the DNA and kills malignant cells.

One of the standout features of this drug is a locking mechanism that ensures the chemical remains attached to the antibody during its journey through the bloodstream. This prevents leakage into the blood, protecting healthy cells and minimizing side effects. The locking mechanism is specifically designed to break only when it attaches to malignant cells, releasing the active ingredient to destroy the tumor from within.

After four cycles of treatment, clinical assessments indicated that Mrs. Dung responded well, with a noticeable reduction in tumor size. The swelling in her neck decreased by 80%, and she reported improved breathing and appetite. Initially diagnosed in 2023, Mrs. Dung had undergone five treatment regimens over three years, but her condition continued to worsen. By March 2026, she was experiencing severe symptoms, including difficulty breathing and extensive skin infections.

Upon her arrival at Tam Anh Hospital, she was treated with antibiotics and anti-inflammatories, alongside nutritional support. Radiation therapy was also administered to alleviate her symptoms. With the identification of HER2-positive breast cancer, the decision was made to initiate treatment with the new ADC therapy.

From being bedridden and severely weakened, Mrs. Dung has regained her ability to eat and walk after starting the new treatment. Although she experienced some side effects, such as nausea and diarrhea in the initial days, these were effectively managed. She continues to receive the treatment every three weeks.

HER2 (human epidermal growth factor receptor 2) is a protein that regulates the growth and survival of cells. The presence of HER2 can cause breast cancer cells to grow rapidly, increasing the risk of recurrence and metastasis. Breast cancer with elevated HER2 levels is termed HER2-positive, while those with low or absent HER2 are classified as HER2-negative.

Dr. Van emphasized that the new ADC therapies provide patients with late-stage breast cancer, who have become resistant to multiple treatment regimens, a chance for extended survival and improved quality of life. In Vietnam, these new targeted drugs are imported through a special drug procurement program authorized by the Ministry of Health. Tam Anh Hospital has been using this treatment for patients since January 2026.