P13 Ovarian granulosa cell tumors treated with estrogen blockade and CDK4/6 inhibitors: A case series

Advanced and recurrent GCTs present a clinical challenge as viable treatment options are limited, and no optimal management strategy has been established. Mutation of FOXL2 has been found to be present in approximately 95% of adult GCTs and leads to increased expression of Cyclin D2 contributing to increased proliferation. In hormone receptor (HR) positive breast cancer, where Cyclin D overexpression is common, CDK 4/6 inhibitors have been associated with significant improvement in progression-free survival when used in combination with endocrine therapy. Considering their efficacy in HR+ breast cancer, this treatment may be of benefit in other HR+ cancers. We report a case series of 4 patients with recurrent GCTs who were treated with CDK 4/6 inhibition in combination with hormone therapy.