Abstract
Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor with nearly universal progression despite aggressive first-line therapy. The Optune device represents an innovative treatment option for patients with recurrent GBM, which utilizes alternating electric fields at an intermediate frequency of 200 kHz, or Tumor Treating Fields (TTFields), to selectively kill or arrest the growth of rapidly dividing cells.
Approximately 15 % of recurrent GBM patients experience a complete or partial radiological response to TTField therapy that typically develops slowly, with a median time to response of 5.2 months, and is generally durable with a median duration of 12.9 months. Some GBM patients have survived 10 years or longer.
In past clinical trials for recurrent GBM, 7 of 16 (44 %) tumors responding to continuous TTFields initially exhibited radiological signs of growth before reversing and regressing in size, at a median time of 4 months. Tumor responses develop gradually and initial tumor growth may be observed even in eventual responders.
Thus, we recommend that TTFields should be continued for a sufficient amount of time and that initial radiologic progression following this therapy should not be considered a reason to discontinue treatment.