Oh my fuck. I hate news stories like this. Aspartame falls into the same cancer risk category as eating red meat sometimes and being kinda lazy. A rigorous systematic review was conducted of dozens of studies of aspartame and they did not find a plausible biologic mechanism by which aspartame could cause cancer. Epidemiologically, it’s vaguely correlated, not causative of cancer.
Also, in the Reuters article it notes that a 132-lbs adult would have to drink 12 to 36 cans of diet coke a day for the dose/exposure to become relevant to the risk they’re talking about. This article is talking about one study that is at odds with the systematically reviewed data from 40 human observational studies, 12 experimental animal studies, and 1360 assay/experimental end points to look for the supposed link.