Trastuzumab the anti-human epidermal growth factor receptor-2 (HER-2) monoclonal antibody, is one of the important options for breast cancer treatment. There are advantages and disadvantages, and some adverse effects may occur with the application of trastuzumab. In addition to disease progression, the most common adverse reactions that lead to discontinuation of treatment are infection, diarrhea and febrile neutropenia. The following is a description of the adverse reactions to trastuzumab.
Infusion reactions
Infusion reactions include a range of symptoms that manifest as fever, chills, occasionally nausea, vomiting, pain (in some patients pain can be at the site of the tumor), headache, dizziness, dyspnea, hypotension, rash, and debilitation.
Severe and fatal infusion reactions have occurred. Severe reactions include bronchospasm, allergic reactions, edema, hypoxia, and severe hypotension, and usually occur during or after the initial infusion. However, the character of the episodes is highly variable and can be gradual, initially improving and then worsening, or occurring with delayed events and deteriorating rapidly. Death occurs within hours or even days after a severe infusion reaction.
The risk of fatal infusion reactions may be elevated in patients with advanced malignancy that causes respiratory distress even at rest. Therefore, physicians treat these patients with great caution, weighing the risks against the benefits.
In all patients who experience dyspnea or severe hypotension, trastuzumab infusion is usually interrupted and medication is given concurrently, and oxygen may be administered. The physician will evaluate and carefully monitor the patient until signs and symptoms have completely resolved. Permanent discontinuation of the drug will be considered for all those who experience a severe infusion reaction.
Embryotoxicity
Trastuzumab use in pregnant women can cause fetal harm. In some patients, the use of trastuzumab during pregnancy has resulted in low amniotic fluid and caused pulmonary hypoplasia, skeletal abnormalities, and neonatal death. As a patient it is important to know that the use of trastuzumab during pregnancy may cause harm to the fetus and that patients of childbearing age should take avoidance measures.
Pulmonary toxicity
Severe pulmonary toxicities have also occurred in those on trastuzumab, and these events have occasionally resulted in death. Pulmonary toxicities that have occurred include interstitial lung disease (including pulmonary infiltrates), acute respiratory distress syndrome, pneumonia, noninfectious pneumonia, pleural effusion, respiratory distress, acute pulmonary edema, and insufficiency. These adverse events can occur as part of an infusion reaction or be delayed. More severe reactions may occur in those with pre-existing symptoms of lung disease or tumor involvement of the lungs resulting in dyspnea even at rest.
Prior or combined use of other antineoplastic treatments known to cause interstitial lung disease, such as paclitaxel, gemcitabine, vinorelbine, and radiation therapy, can lead to an increased risk of interstitial lung disease.
People with dyspnea even at rest due to advanced malignancy are at increased risk for pulmonary events. Therefore, trastuzumab therapy is not usually chosen by physicians for these patients.
Chemotherapy-induced neutropenia
In studies of trastuzumab in combination with chemotherapy for metastatic breast cancer, a higher rate of severe neutropenia occurred in those with the combination of myelosuppressive chemotherapeutic agents than in those with chemotherapy alone.
While trastuzumab has the potential to cause adverse reactions, the risk of adverse reactions should not be a reason to “stay away” from it. The decision to use trastuzumab will be made by the physician on a patient-by-patient basis. (Contributed by Yang Yuqing, Department of Nail and Breast Vascular Surgery, Xijing Hospital, Air Force Military Medical University)