image: Figure 1: CE MRI at BM and LMC initial moment of diagnosis. Heterogeneous space-occupying lesion (right posterior parietal-parasagittal cortico-subcortical area), with vasogenic edema and sulcal effacement, compatible with a BM lesion, along with pachymeningeal carcinomatosis (right next to the first described BM).
Credit: Copyright: © 2025 Martins et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
“This solid evidence is seemingly leading into a new and groundbreaking BC treatment era.”
BUFFALO, NY — November 5, 2025 — A new case report was published in Volume 12 of Oncoscience on October 9, 2025, titled "Metastatic breast cancer with leptomeningeal carcinomatosis treated with trastuzumab deruxtecan – a case report."
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 had spread to the membranes surrounding the brain and spinal cord—a condition known as leptomeningeal carcinomatosis.
The patient, a 37-year-old woman, initially responded to standard treatment but experienced a relapse two years later. At that point, her cancer had progressed to involve the central nervous system, severely affecting her neurological function. Given the complexity of her condition and limited standard options, the medical team initiated off-label treatment with trastuzumab deruxtecan.
Trastuzumab deruxtecan, a targeted antibody-drug conjugate, was selected based on data from recent clinical trials and multidisciplinary discussions. The patient began to improve after three treatment cycles. Imaging showed a reduction in the size and extent of the cancer, and her neurological symptoms gradually improved, allowing her to regain independence in daily activities. She continued on treatment for more than two years, during which the disease in her brain and spinal membranes remained stable.
This case illustrates the potential of antibody-drug conjugates like trastuzumab deruxtecan in treating breast cancers that reach the central nervous system. It also underscores the need for personalized and flexible treatment approaches in oncology, especially in cases of advanced or treatment-resistant breast cancer. Therapies like trastuzumab deruxtecan may become important tools for managing these types of tumors.
Continue reading: https://doi.org/10.18632/oncoscience.631
Correspondence to: Cristiana Honrado Martins - cristiana.honrado.martins@ulsb.min-saude.pt
Abstract video: https://www.youtube.com/watch?v=7CplmXaDyvc
Keywords: cancer, breast cancer, leptomeningeal carcinomatosis, HER2 positive, antibody-drug conjugate, trastuzumab-deruxtecan
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About Oncoscience:
Oncoscience is a peer-reviewed, open-access, traditional journal covering the rapidly growing field of cancer research, especially emergent topics not currently covered by other journals. This journal has a special mission: Freeing oncology from publication costs. It is free for the readers and the authors.
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Journal
Oncoscience
Method of Research
Case study
Subject of Research
People
Article Title
Metastatic breast cancer with leptomeningeal carcinomatosis treated with trastuzumab deruxtecan – a case report
Article Publication Date
9-Oct-2025
COI Statement
Authors have no conflicts of interest to declare.