Is re-radiation for glioblastoma after progression associated with increased survival: to treat or not to treat?

Glioblastoma is the most common malignant brain tumor, representing 53.8% of all gliomas (1). Despite standard of care treatment with radiation and temozolomide chemotherapy, glioblastoma has a dismal prognosis with median survival of 14.6 months (2) and 20.9 months with addition of tumor-treating fields (Optune) (3). After tumor progression, treatment with re-irradiation and/or systemic therapy has yet to show improved overall survival leading to disagreement as to the best management of the patient who has progressed after standard of care treatment.