Abstract
A 76-year-old woman had recurrent breast cancer (BC) with carcinomatous pleuritic and multiple liver metastases 15 years after BC surgery. Despite sequential endocrine therapy and chemotherapy, her condition deteriorated with the development of hepatic failure. Her performance status (PS) was 4, but the patient wanted to continue treatment. Therefore, very-low-dose ethinyl estradiol (EE2) 0.5 mg/day was started to avoid any adverse effects. After 7 days, the patient's overall condition improved, and the jaundice decreased ; after 1 month, her tumor markers decreased. A partial response was achieved over the following 6 months. Although a relatively high incidence of adverse events with EE2 has been reported, no adverse events occurred in this patient. Based on our search of the literature, BC response to EE2 at doses ≤ 1.0 mg/day has not been reported. Thus, this interesting case is reported.
