The name is new but "ultra processed" - which is to say processed - has been with us for 50 years nowadays. Deleterious effects are known: obesity, diabetes and, yes, uptake in cancers.
Still, an unlikely candidate for a recent uptake in cancers amongst the young at least as a general category and not aiming at a specific new class of additives.
Its hard to make assumptions like this though. There is always the possibility that prolonged exposure to processed foods impacts reproduction over time. We could be seeing a delayed spike now because parents were exposed to the food for a decade or two before they had children.
This is all hypothetical, I'm not claiming this is the case. Its just worth considering delayed responses that require a generation or two before the symptoms are easy to spot.
I think we reached a point where we shouldn't even call them "food", but "edible industrial products".