Stabilization of Metastatic Uterine Leiomyosarcoma Using Pembrolizumab

The estimated 5-year survival rate for patients with stage IV uterine leiomyosarcoma is 29%, with a median survival of <1 year. This report describes a patient with stage IVB leiomyosarcoma who experienced stable disease for 15 months on pembrolizumab. A woman aged 62 years, gravida 2 para 2, with postmenopausal bleeding and a necrotic uterine fibroid underwent a dilation and curettage and was diagnosed with uterine leiomyosarcoma. CT imaging showed pulmonary and bony metastasis. She underwent surgical staging with biopsy-proved stage IVB disease. A mixed partial response was noted using first- and second-line chemotherapy. Molecular tumor profiling confirmed PD-L1 expression. The patient was started on pembrolizumab, and at the time of writing she is status post 23 cycles with stable disease. Pembrolizumab was well tolerated and aided prolonged disease stabilization.