{
  "abstract": "Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate approved for the treatment of unresectable or metastatic human epidermal growth factor receptor 2 (HER2)-positive breast cancer in patients who have received a prior anti-HER2-based regimen. HER2-positive breast cancer has a high propensity for central nervous system (CNS) spread, which confers significant morbidity and a poor prognosis. We report the case of a 47-year-old woman with metastatic HER2-positive breast cancer who developed debilitating symptomatic CNS metastases, predominantly extra-axial leptomeningeal lesions. Locoregional treatment options were not feasible, and the patient received off-label first-line systemic therapy with T-DXd. Rapid and marked neurological improvement was observed within weeks. Follow-up MRI at three months demonstrated complete radiologic resolution of all CNS lesions. As of April 2026, after 29 cycles of T-DXd, the patient remains clinically asymptomatic with no evidence of CNS disease on MRI, corresponding to a progression-free survival exceeding 20 months. This case highlights the potential role of T-DXd in symptomatic CNS metastases, particularly leptomeningeal disease, and underscores the need for prospective research into its intracranial efficacy in this distinct and challenging subset of patients.",
  "abstract_shown": true,
  "affiliations": [
    "Medical Oncology, Unidade Local de Saúde (ULS) São João, Porto, PRT.",
    "Surgery, Unidade Local de Saúde (ULS) São João, Porto, PRT."
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Maria João Oura"
    },
    {
      "affs": [
        0
      ],
      "name": "Rita Pinho"
    },
    {
      "affs": [
        1
      ],
      "name": "Fernando Osório"
    },
    {
      "affs": [
        0
      ],
      "name": "Miguel Barbosa"
    },
    {
      "affs": [
        0
      ],
      "name": "Ana Valente"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/00qd87m6dnkta.bib",
  "cited_by": 0,
  "doi": "10.7759/cureus.116819",
  "fulltext_url": "https://europepmc.org/articles/PMC13695090",
  "id": "00qd87m6dnkta",
  "issns": [
    "2168-8184"
  ],
  "landing_url": "https://europepmc.org/article/MED/42927259",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2740|Brain Metastases and Treatment"
    ]
  ],
  "openalex": "W7214150327",
  "pdf_url": "https://europepmc.org/articles/PMC13695090?pdf=render",
  "pmcid": "PMC13695090",
  "pmid": "42927259",
  "published": "2026-09-24",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/00qd87m6dnkta.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:18Z",
      "native_id": "MED:42927259",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42927259"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2740|Brain Metastases and Treatment",
      "subfield": "general"
    }
  ],
  "title": "Complete Response to First-Line Trastuzumab Deruxtecan in Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Extra-axial Central Nervous System Metastases.",
  "title_text": "Complete Response to First-Line Trastuzumab Deruxtecan in Human Epidermal Growth Factor Receptor 2 (HER2)-Positive Extra-axial Central Nervous System Metastases.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:21:18Z",
  "url": "https://research.draconitic.com/paper/00qd87m6dnkta",
  "venue": "Cureus",
  "versions": []
}