High-dose fulvestrant as third-line endocrine therapy for breast cancer metastasis to the left kidney: A case report and literature review

RATIONALE: Endocrine therapy plays an important role in the treatment of patients with hormone receptor-positive breast cancer. Renal metastasis of breast cancer is rare in clinical practice. PATIENT CONCERNS: We present here a 54-year-old woman with breast cancer after first line chemotherapy and second line endocrinotherapy (i.e., toremifene & exemestane) failure. DIAGNOSES: The patient was rarely diagnosed breast cancer metastasis to the kidney and a positive hormone status (ER and PR) but was negative for human epidermal factor receptor 2 (HER2). INTERVENTIONS: The patient was treated with a high dose of fulvestrant (SERD; 500 mg) by intramuscular injection once per month. OUTCOMES: The patient's condition significantly improved as measured by a decrease in the renal and pulmonary masses; symptoms including dry cough and blood phlegm also improved. LESSONS: Endocrinotherapy with high-dose fulvestrant may provide benefits for patients with HR+/HER2− advanced breast cancer with renal metastasis after SERMs failure.