The Double-edged Sword of Targeted Therapy: Trastuzumab Deruxtecan-induced Interstitial Lung Disease in Breast Carcinoma: A Case with Review
Year: 2026
Type: article
Study design: Case Report
Abstract: Case DesCriptionA 66-year-old female, a homemaker with a history of well-controlled hypertension and hypothyroidism, presented to our institute in April 2023 with complaints of a progressively enlarging right breast lump.On clinical examination and biopsy, she was diagnosed with invasive ductal carcinoma, grade 3, estrogen receptor (ER) and progesterone receptor (PR) negative, and HER2-positive, introDuCtion Breast cancer remains the most common malignancy among women worldwide, with human epidermal growth factor receptor (HER2) positivity reported in approximately 15-20% of cases and associated with aggressive disease biology and poorer prognosis.1 The advent of HER2-targeted therapies has significantly improved survival outcomes in this subgroup.Trastuzumab deruxtecan (T-DXd), a novel antibody-drug conjugate (ADC), combines a humanized anti-HER2 monoclonal antibody with a cleavable linker and a potent topoisomerase I inhibitor payload (deruxtecan).2 This unique design provides not only direct cytotoxicity but also a "bystander effect," enabling activity even in HER2-low tumors.3 While T-DXd has transformed the therapeutic landscape in HER2-positive and HER2-low metastatic breast cancer, it carries a distinct toxicity profile.The most concerning adverse event is interstitial lung disease (ILD)/ pneumonitis, which can be life-threatening.Across pivotal trials such as DESTINY-Breast01, 03, and 04, ILD incidence has ranged between 9 and 15%, with fatal cases reported despite proactive monitoring.[4][5][6] The risk appears to be dose-dependent and typically emerges within the first year of therapy.Recognizing clinical and radiological features early, excluding infectious or malignant differentials, and instituting prompt corticosteroid therapy are essential to improving outcomes.7 We report here a case of T-DXd-associated ILD in a patient with stage IV right breast carcinoma, highlighting the diagnostic and management challenges, followed by a review of the literature.
Source: Journal of PACS
Authors: Anil Kumar Singh, Huda Shamim, Vaibhava Srivastava, Rahul Sharma, Rajat Kumar Mishra
Language: English
Topic: HER2/EGFR in Cancer Research
Subfield: Oncology
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7147017637