The NCCN guidelines are important because many insurance plans base their payment decisions upon these guidelines! The new version lists "alternating electric field therapy" (Novocure TTF100-A is the only FDA approved alternating electric field therapy device) as an option for both local or multiple/diffuse recurrences of GBMs.
To view the guidelines, go to:
www.nccn.org/professionals/physician_gls/pdf/cns.pdf
A free registration is required