Glioblastoma multiforme (GBM) is difficult to treat due to microscopic tumor fingers on the periphery and the risk of causing brain necrosis with radiation.

“I think it just has to do with the the invasiveness of the fingers of the tissue in terms of even when it you think you've gotten the whole thing uh there's microscopic fingers that are always on the periphery and you can't just radiate it indiscriminately like you can other parts of the body because you've got the brain there so yet there's a there's always a a fine line you're walking between causing you know say for example necrosis of the brain versus letting the tumor recur and so that's really the number one issue”