Maybe, but has earlier detection really impacted GBM much? It's not like breast or testicular cancer - we can't encourage the population to "examine your brain

Maybe, but has earlier detection really impacted GBM much? It's not like breast or testicular cancer - we can't encourage the population to "examine your brain for lumps". Even today someone could have no obvious symptoms of GBM one day, then have a seizure while driving and die in a car crash the next day. Though I guess if car crashes were a common cause of death that doesn't require autopsy, you'd see some difference in GBM rates between car heavy places like the US, vs places with better public transit like EU.