A new case report titled " Metastatic Breast Cancer with Leptomeningeal Carcinomatosis Treated with Trastuzumab Deruxtecan – A Case Report " was published on October 9, 2025, in Volume 12 of Oncoscience.
In this report, Cristiana Honrado Martins, José Miguel Rocha, Catarina Portela, Ricardo Fernandes, and Cláudia Caeiro from Hospital de Braga, ULS de Braga, describe a rare case of advanced HER2-positive breast cancer (BC) that has spread to the membranes surrounding the brain and spinal cord – a condition known as leptomeningeal carcinomatosis.
The 37-year-old patient initially responded to standard therapy but relapsed two years later. By this time, the cancer had spread to the central nervous system, severely impairing her neurological functions. Due to the complexity of her condition and limited standard treatment options, the medical team initiated off-label treatment with Trastuzumab Deruxtecan.
Trastuzumab Deruxtecan, a targeted antibody-drug conjugate, was selected based on data from current clinical studies and multidisciplinary consultations. After three cycles of treatment, the patient's condition showed improvement. Imaging studies confirmed a reduction in tumor size and extent, and her neurological symptoms gradually improved, allowing her to regain independence in daily activities. Treatment continued for two years, during which the disease remained stable in the brain and spinal cord.
This case highlights the potential of antibody-drug conjugates like Trastuzumab Deruxtecan in treating breast cancer with central nervous system involvement. It also underscores the need for personalized and flexible therapeutic approaches in oncology, especially for advanced or treatment-resistant breast cancer. Therapies such as Trastuzumab Deruxtecan may prove to be important tools in managing these types of tumors.
Read more: https://doi.org/10.18632/oncoscience.631
