Clear cell carcinoma of the ovary: Epidemiology, pathological and biological features, treatment options and clinical outcomes.

Clear cell carcinoma of the ovary is a rare and distinct histotype of epithelial ovarian carcinomas. Women diagnosed with clear cell carcinomas are usually younger and diagnosed at earlier stages than those with the most common high-grade serous histology. Endometriosis is considered a main risk factor for the development of clear cell carcinoma of the ovary, and it can be considered a precursor of of this tumor, as it is identified in more than 50% of patients with clear cell carcinoma. Different molecular pathways and alterations heve been identified in ovarian clear cell carcinoma, including the most common mutations of AT-rich interaction domain 1A [ARID1A] and phosphatidylinositol-4,5-bisphosphate 3-kinase [PIK3] catalytic subunit alpha [PIK3CA]. The prognosis of patients at early stage is favorable, while patients with advanced or recurrent disease experience a poor oncologic outcomes. Despite a lower rate of responses due to an intrinsic chemoresistance, the treatment strategy for advanced disease resembles the treatment of high-grade serous carcinoma, which includes aggressive cytoreductive surgery and platinum-based chemotherapy. For this reason, the role of adjuvant chemotherapy in patients with stage I disease undergoing complete surgical staging is still under debate. Alternative treatments, including biological agents that target different pathways constitute the most promising treatment strategies, and well-designed, collaborative international trials should be designed in order to improve the oncologic outcomes and the quality of life of patients with this aggressive disease.