Trastuzumab deruxtecan in the treatment of adult patients with HER2-positive breast cancer

In 2020, approximately 18,000 women in Poland were diagnosed with breast cancer, and 6,000 of them died. In recent years, we have witnessed significant progress in the diagnosis and treatment of breast cancer patients. When detected early and treated appropriately, the prognosis is very good, and even some patients with distant metastases have experienced long-term survival. The most common biological subtype is hormone receptor-positive breast cancer, accounting for about 70% of diagnoses, showing expression of estrogen and progesterone receptors. Triple-negative breast cancer and HER2-positive breast cancer each make up approximately 15% of all cases. In the treatment of advanced HER2-positive breast cancer, a combination of docetaxel with pertuzumab and trastuzumab is used in the first line. In subsequent lines of treatment, options include trastuzumab deruxtecan (T-DXd), trastuzumab emtansine, lapatinib, tucatinib, margetuximab, and trastuzumab. Trastuzumab derukstekan is an immunoconjugate that, upon entering the cell, releases a cytostatic agent that destroys its genetic material and neighboring cells (the "bystander effect"). It significantly prolongs the time to disease progression and overall survival compared to standard treatments used in the second and subsequent lines of treatment. It represents an effective and valuable therapeutic option for patients with early-stage HER2positive metastatic breast cancer.