Role of immunotherapy in chondrosarcoma: A case report and review of the literature.

Chondrosarcomas (CSs) consist of a heterogenous group of primary bone cancers arising from malignant cells which produce cartilaginous matrix. As the second most common primary bone cancer, CS are often resistant to systemic chemotherapy due to poor vascularization, slow proliferation, and expression of multidrug-resistant pumps. Immune checkpoint inhibitors have transformed the field of oncology and are now designated as frontline therapy for many solid tumor cancers. Several studies have demonstrated increased expression of programed cell death 1 (PD-1) and PD-L1 in CS tissue , which has led to the development of multiple clinical trials for immunotherapy in patients with aggressive CS. In this review, we highlight the ongoing investigation into the role for immunotherapy in CS. We also report the case of a 44-year-old female with a history of stage IV primary CS of the right shoulder who underwent radical resection with recurrence and demonstrated a spectacular sustained response to pembrolizumab at our center. Our review highlights the need for further studies investigating the role of immunotherapy in the treatment of aggressive bone sarcomas that are resistant to standard surgical resection, chemotherapy, and radiation treatment.