HER2-TARGETED THERAPIES

Diagnosis

MC is a 65-year-old female who noted a lump in her right breast in 2013. She underwent a mammogram and was noted to have a 4.5-cm mass. Biopsy indicated ER+/PR+ HER2+ for invasive ductal carcinoma. Assessment of her lymph nodes indicated that 11 nodes were positive for disease.

Treatment

MC underwent a modified radical mastectomy. She then received docetaxel/carboplatin/trastuzumab (TCH) for 6 cycles, followed by radiation therapy and trastuzumab x 7 months. She started exemestane in the fall of 2013. In April 2018, MC reported to her local oncologist with complaints of shortness of breath and a cough for 1 month. She had a PET/CT scan that demonstrated lung and liver lesions. Transthoracic echocardiogram (TTE) indicated a normal left ventricular ejection fraction (LVEF). She underwent a liver biopsy that demonstrated recurrent disease that was now ER-/PR- HER2+. She was started on THP (docetaxel/trastuzumab/pertuzumab) in April 2018.

In August, the docetaxel was stopped, and MD continued on trastuzumab and pertuzumab (HP). In November 2019, she traveled to India with plans to continue therapy with HP; however, she did not continue her therapy. She then was noted to have slurred speech and a headache, and was discovered to have brain metastasis. She returned to the US and was treated with whole-brain radiation therapy and was started on carboplatin/gemcitabine and trastuzumab. After 6 months of treatment, she presented with increasing shortness of breath but no new lung lesions. Echocardiogram indicated that her LVEF was 35%.

Cardiotoxicity Mitigation and Management

MC was referred to cardiology and started on metoprolol and lisinopril. Two months later, her echocardiogram indicated that her LVEF was 45%. After a total of 6 months on the metoprolol and lisinopril, MC reported having abdominal discomfort. CT demonstrated new liver lesions. Her LVEF on echocardiogram was 55%. She was restarted on carboplatin/gemcitabine and trastuzumab.