A 75-year-old woman presents to the physician with a new left breast mass. She has a history of type 2 diabetes mellitus and tobacco use. She takes metformin and glipizide. Ultrasound confirms the presence of a mass, and a biopsy confirms the presence of breast cancer with is human epidermal factor receptor 2 (HER2) positive. Further evaluation reveals the presence of metastatic disease. Her oncologist recommends initiation of neoadjuvant chemotherapy plus trastuzumab (Herceptin).
Which of the following side effects is most likely with trastuzumab?
The correct answer is:
B) Cardiotoxicity
This patient has Her2 positive metastatic breast cancer which requires neoadjuvant chemotherapy along with trastuzumab. HER2 plays an important role in the signaling network that drives cell proliferation. Trastuzumab is believed to block intracellular signaling pathways by attenuating the signal transduction downstream. One of its main side effects is cardiotoxicity, though the underlying pathophysiology is not fully understood. Cardiotoxicity due to trastuzumab most often manifests as an asymptomatic decrease in left ventricular ejection fraction though it may present with heart failure. All patients on trastuzumab should have their cardiac function evaluated with echocardiography prior to initiation of therapy and for the duration of therapy, though the optimal surveillance schedule is not defined.
Answer choice A: Hepatotoxicity, is incorrect. Hepatotoxicity is not a concern with trastuzumab.
Answer choice C: Nephrotoxicity, is incorrect. Renal toxicity due to trastuzumab is rare.
Answer choice D: Neurotoxicity, is incorrect. Though trastuzumab can cause some neurologic symptoms such as dizziness and headache, neurotoxicity is not a significant concern.
Answer choice E: Pulmonary toxicity, is incorrect. Trastuzumab may cause pulmonary toxicity which can be life-threatening, though this is rare.
Key Learning Point
Trastuzumab and other anti-HER2 antibodies can cause cardiotoxicity and require monitoring of cardiac function during therapy.
