To be clear, saying this can cause cancer is similar to saying that water will be classified as toxic.
Cancer is a genetic/cellular lottery we play every day. Consuming certain substances can change those odds. We’re talking 1 in a Trillion (a number I pulled out of my ass, to be clear), and perhaps consuming aspartame changes that to 100 in a Trillion. 100x more likely to get cancer? Not really.
Just like how water is classified as toxic if you drink too much (cellular over-hydration) consuming too much aspartame can cause cancer.
Though I suppose it remains to be seen. I’m making broad assumptions and I’ll wait for the professionals and studies and scientific journals to tell me what’s what.