[HER2-Positive Breast Cancer with Severe Infusion Reaction to Pertuzumab plus Trastuzumab-A Case Report].

A 64-year-old woman detected a tumor in her left breast in July 2015, and the tumor became exposed and ulcerated in January 2016. Subsequently, the tumor began to bleed, and the patient was admitted to our hospital on an emergency basis in March 2016. A CT scan revealed the presence of a giant tumor in the left breast, accompanied by chest wall infiltration, left axillary lymph node metastasis, and multiple liver and bone metastases. Following needle biopsy, the specimen was diagnosed as Luminal-HER2-type invasive ductal carcinoma, and pertuzumab plus trastuzumab plus docetaxel was administered. Upon administration of 2/3 of the pertuzumab, the patient developed chills. Therefore, the administration rate was reduced; however, the patient experienced palpitations, nausea, tachycardia, and decreased blood pressure at the end of the administration. Pertuzumab was temporarily discontinued, a replenisher was infused, and the symptoms improved within approximately 20 minutes. However, the patient again experienced chills, tachycardia, and decreased blood pressure immediately after reinitiating trastuzumab administration and complained of strong pain at the tumor site. Continuation of chemotherapy was deemed dangerous, and administration was discontinued. It has been reported that infusion reactions to trastuzumab are associated with clinical stage. In this case, the symptoms of the infusion reaction were severe because of the large tumor volume. It is necessary to consider administration of premedication and the administration time of anti-HER2 drugs in cases with high tumor burden such as the current case.