Rethinking of treatment strategies and clinical management in ovarian clear cell carcinoma

Ovarian clear cell carcinoma (OCCC), with unique clinical and molecular characteristics compared with other histological types of epithelial ovarian cancer (EOC), behaves like a distinct entity and has a poorer prognosis than other EOC types, especially in advanced stages. In addition, OCCC comprises approximately 27% of all EOC cases in Japan, compared with 12% in Western countries. Historically, patients with OCCC have been eligible for chemotherapeutic and surgical trials of EOC. It has been difficult to evaluate the specific impact of these trials on the prognosis of women with OCCC because of its rarity and unique molecular characteristics. Recent studies of OCCC revealed significant molecular variations related to carcinogenesis and molecular targets that could directly facilitate patient stratification and subsequent precision medicine. Thus, treatment strategies specific for OCCC based on its clinical and molecular characteristics are urgently needed. In this review, we highlight the management and treatment of OCCC from clinical aspects.