Oh, what a surprise, zapping brains with radiation might have some downsides—who would’ve thought? In a stunning revelation that’s sure to shock the medical community, researchers have been scratching their heads to figure out if frying the fornix with radiotherapy could possibly lead to something as unexpected as symptomatic radiation necrosis (SRN). Spoiler alert: it does.

So, they rounded up 67 brave souls who had their anaplastic oligodendrogliomas treated between 2009 and 2019, and they played a guessing game of ‘Will it necrose?’ using the most sophisticated criteria. They drew some fancy lines around various brain bits, including the fornix, and then crunched numbers to see if there was a magical radiation dose that wouldn’t turn brains into mush.

Most of these patients had a frontal lobe shindig, and more than half had their tumors scooped out completely. A lucky 63% got a cocktail of chemotherapy that’s as easy to pronounce as a cat walking on a keyboard. After a median follow-up of 42 months, the median survival times were impressive, but let’s not forget the 24% who drew the short straw and developed SRN.

Drum roll, please… Turns out, if you’re older than 46 and your fornix gets more than 59 Gy of radiation, you’re in the danger zone. The rate of SRN was higher in patients who got a heftier dose to the fornix—43% compared to a mere 13% for those who got less. Who knew?

The conclusion? Maybe, just maybe, not blasting the fornix to kingdom come could be a good idea. But hey, let’s not jump to conclusions—more studies are needed, because it’s not like we can just take a hint from common sense, right?