Would absolutely agree that you’d want a second opinion at a major tertiary center with a very experienced good neurosurgeon.
I think in the Stupp trial They had something like 5% that were inoperable and patients just had a biopsy only for diagnosis. I do agree with you that a large subtotal resection probably would have enough tissue to make the vaccine.
But usually when they say in operable it’s because the tumor is in an eloquent area that cannot be removed. Or so central that it is in vital structures in the brain. Basically a resection in some of those areas leads the patient worse off With severe neurologic deficit. Hence inoperable.