Glioblastoma multiforme (GBM) is the most common and malignant primary 
intracranial tumor, and has a median survival of only 10 to 14 months with only 
3 to 5% of patients surviving more than three years. Recurrence (RGBM) is nearly 
universal, and further decreases the median survival to only five to seven 
months with optimal therapy. Tumor-treating fields (TTField) therapy is a novel 
treatment technique that has recently received CE and FDA approval for the 
treatment of RGBM, and is based on the principle that low intensity, 
intermediate frequency electric fields (100 to 300 kHz) may induce apoptosis in 
specific cell types. Our center was the first to apply TTField treatment to 
histologically proven GBM in a small pilot study of 20 individuals in 2004 and 
2005, and four of those original 20 patients are still alive today. We report 
two cases of GBM and two cases of RGBM treated by TTField therapy, all in good 
health and no longer receiving any treatment more than seven years after 
initiating TTField therapy, with no clinical or radiological evidence of 
recurrence.