Trastuzumab-Induced Interstitial Lung Disease: A Case Report

Abstract We present the case of an adult woman, with a history of controlled hypothyroidism and osteoporosis, which comes to the institute with a clinical picture of a tumor in the right breast. Chest tomography showed bronchiolectasis; metastatic subcarinal adenopathy; tumor in the right breast and infiltrative axillary lymphadenopathy; a breast biopsy was performed with results compatible with pure HER2 subtype NOS carcinoma. It was classified as oligometastatic disease, so she began neoadjuvant therapy with adriamycin/cyclophosphamide for 4 courses and trastuzumab/paclitaxel for 4 courses. Then, she underwent conservation surgery, obtaining a complete pathological response, and continued with trastuzumab until progression. On the fifth course, she developed cough and progressive dyspnea; the imaging study revealed severe diffuse interstitial lung disease that was refractory to treatment, leading to the patient's death. It is suggested to take into account that the use of trastuzumab can trigger diffuse interstitial lung disease that can be fatal. Keywords: Breast cancer; Trastuzumab; Diffuse interstitial lung disease; Case report