Tumor-treating fields (TTFields) are transcutaneously delivered alternating electric fields previously approved for treating recurrent glioblastoma. TTFields are hypothesized to have an anti-mitotic activity that impedes cellular proliferation. Stupp et al.1 recently reported an interim analysis of a Phase III multicenter randomized trial comparing the use of TTFields with temozolomide (TMZ) versus TMZ alone for maintenance in patients with newly diagnosed glioblastoma after maximal surgery followed by standard chemoradiation. The TTFields and TMZ group (n=210) showed improved median progression-free survival (7.1 months [95% CI, 5.9-8.2 months) versus 4.0 months [95% CI, 3.3-5.2 months], p=0.001) compared to the TMZ alone group (n=105). The TTFields and TMZ group also showed improved median overall survival compared to TMZ alone (20.5 months [95% CI, 16.7-25.0 months] versus 15.6 months [95% CI, 13.3-19.1 months], p=0.004). Of note, the study was not blinded or placebo-controlled. This data enabled FDA approval of TTFields combined with TMZ in treatment of newly diagnosed glioblastoma.