A 48-year-old woman is evaluated for a painless lump in the right breast, which was first noticed by the patient 3 weeks ago. She has no prior medical problems and has had no mammograms. Her aunt was diagnosed with breast cancer at age 60. Physical examination reveals a 1 x 1.5 cm, firm, mobile mass in the upper outer quadrant of the right breast with no skin or nipple changes. There are no enlarged axillary or cervical lymph nodes. Mammography shows a spiculated mass, and fine-needle aspiration biopsy is positive for invasive ductal carcinoma. The patient undergoes right mastectomy and axillary lymph node dissection. Tumor analysis is negative for estrogen and progesterone receptors but positive for human epidermal growth factor receptor 2 (HER2) gene amplification. Adjuvant therapy containing trastuzumab is planned. Which of the following is most appropriate prior to starting the medication in this patient?

Question

A 48-year-old woman is evaluated for a painless lump in the right breast, which was first noticed by the patient 3 weeks ago.  She has no prior medical problems and has had no mammograms.  Her aunt was diagnosed with breast cancer at age 60.  Physical examination reveals a 1 x 1.5 cm, firm, mobile mass in the upper outer quadrant of the right breast with no skin or nipple changes.  There are no enlarged axillary or cervical lymph nodes.  Mammography shows a spiculated mass, and fine-needle aspiration biopsy is positive for invasive ductal carcinoma.  The patient undergoes right mastectomy and axillary lymph node dissection.  Tumor analysis is negative for estrogen and progesterone receptors but positive for human epidermal growth factor receptor 2 (HER2) gene amplification.  Adjuvant therapy containing trastuzumab is planned.  Which of the following is most appropriate prior to starting the medication in this patient?

Quizplus · Accepted Answer

Trastuzumab is a monoclonal antibody often used in combination with adjuvant chemotherapy in patients with human epidermal growth receptor 2 (HER2)-positive breast carcinoma. Cardiotoxicity is a known adverse effect of trastuzumab that usually manifests as an asymptomatic decline in left ventricular ejection fraction; however, overt heart failure can occur. The risk and extent of cardiotoxicity are amplified when trastuzumab is used in combination with chemotherapy agents that are also cardiotoxic (eg, doxorubicin). Prior to initiating trastuzumab, patients should undergo a baseline assessment of cardiac function by echocardiography. In addition, cardiac function should be reassessed by echocardiography at regular intervals during therapy. Therapy should be discontinued in patients who develop symptomatic heart failure or a significant decline in ejection fraction (eg, >16 percentage points from baseline). The cardiotoxicity associated with trastuzumab is typically reversible, with patients experiencing complete recovery of cardiac function following treatment discontinuation. > cardiotoxicity (Choice A) Ototoxicity is a common side effect of platinum-based chemotherapy (eg, cisplatin, carboplatin). Therefore, baseline audiometry should be performed prior to initiation of these agents. (Choice B) Aromatase inhibitors (eg, anastrozole, letrozole) are used in the treatment of postmenopausal estrogen receptor-positive breast cancer and increase the risk of osteoporosis. Baseline bone density scans should be obtained prior to treatment. (Choice C) Baseline bone marrow biopsies are not routinely obtained prior to the initiation of cancer therapy. However, a biopsy to evaluate bone marrow suppression may be indicated during therapy with antimetabolite chemotherapeutic agents (eg, 5-fluorouracil, methotrexate). (Choice E) Tamoxifen is used in the treatment of estrogen receptor-positive breast cancer and increases the risk of venous thromboembolism. Patients with factor V Leiden mutation are at increased risk of venous thromboembolism, and testing for the mutation is sometimes indicated prior to initiation of tamoxifen. (Choice F) Bleomycin can cause pulmonary fibrosis; pulmonary function testing should be obtained at baseline and at regular intervals in most patients receiving bleomycin chemotherapy. (Choice G) Tumor necrosis factor-alpha inhibitors are used in the treatment of rheumatologic disease and can cause reactivation of latent tuberculosis. Prior to initiating therapy with these agents, tuberculosis skin testing is recommended. Educational objective: Trastuzumab is used for the treatment of patients with human epidermal growth receptor 2-positive breast carcinoma and is associated with a risk of cardiotoxicity. Cardiac function should be assessed with echocardiography at baseline and at regular intervals in patients treated with trastuzumab. References: Trastuzumab-associated cardiotoxicity. (http://www.ncbi.nlm.nih.gov/pubmed/12237930) Cardiotoxicity associated with trastuzumab treatment of HER2+ breast cancer. (http://www.ncbi.nlm.nih.gov/pubmed/19669637)

A 48-Year-Old Woman Is Evaluated for a Painless Lump in the Right