JRSBRT 8.4, p. 321-324

Stereotactic body radiation therapy for an unresectable fgf23-secreting tumor of the cervical spine: a case report and literature review
Kathryn Hockemeyer, Juhi M. Purswani, Joseph K Kim, Babak Givi, Elcin Zan, Donato Pacione, Maksim Shapiro, Ilya Laufer, Jill B. Feffer and Joshua S. Silverman

We present the case of a 65-year-old male with tumor-induced osteomalacia (TIO) caused by an FGF23-secreting phosphaturic tumor of C2 treated definitively with stereotactic body radiation therapy (SBRT) and kyphoplasty. The patient exhibited notable reduction in FGF23 6 weeks following radiotherapy. He also received a dose of the FGF23 monoclonal antibody, burosumab. We discuss the case with emphasis on radiation in the management of TIO. This case demonstrates SBRT as a well-tolerated local treatment option for the management of unresectable FGF23-producing tumors.

Keywords: SBRT, FGF-23, tumor-induced osteomalacia, kyphoplasty