28 months progression-free survival after pyrotinib therapy for HER2-positive recurrent ovarian clear cell carcinoma: a case report

Background: Ovarian cancer (OC) is the seventh most common newly diagnosed cancer in women worldwide. Ovarian clear cell carcinoma (OCCC) is a specific type of epithelial ovarian cancer with a poor prognosis. It has been revealed that human epidermal growth factor receptor 2 (HER2)-positive (2+/3+) has been observed in 6.7% to 45.6% of patients with OCCC. Anti-HER2 therapy has been demonstrated to be an effective strategy for the treatment of HER2-positive breast cancer. However, the role of anti-HER2 therapy in OC remains largely unknown. This case report is the first report suggesting a 28 months PFS of pyrotinib in HER2-positive OCCC. Case Description: A 67-year-old female patient with HER2-positive OCCC was admitted to our hospital because of fever, who benefited greatly from treatment with pyrotinib, an irreversible HER2 antagonist conditionally approved for patients with advanced or metastatic HER2-positive breast cancer in China. The patient, who had previously been diagnosed with stage I-A OCCC [according to the International Federation of Gynecology and Obstetrics (FIGO)] and undergone radical surgery with standard adjuvant chemotherapy on May 15, 2017, was diagnosed with HER2-positive OCCC at FIGO stage IIIC. She was treated with oral pyrotinib (400 mg/day in 21-day cycles) starting on November 27, 2018. Imaging assessments were conducted every 2 to 4 treatment cycles. Best response by response evaluation criteria in solid tumors (RECIST) 1.1 were partial response. However, on March 30, 2021, the patient was assessed using contrast-enhance CT and found to have progressive disease with liver metastases. Subsequently, on April 26, 2021, the patient underwent liver microwave ablation and ultrasound-guided liver biopsy. The immunohistochemistry results of the liver biopsy showed the origin of the disease to be ovarian. Therefore, the disease was identified as HER2-positive OCCC at FIGO stage IVB. Conclusions: Progression-free survival (PFS) in second-line chemotherapy for patients with recurrent OC ranges from 3.8 to 11.3 months. In the case of this patient, treatment with pyrotinib yielded a PFS of 28 months, which was a promising result for the use of pyrotinib in treating HER2-positive OC.