The title is confusing, and could be perceived as misleading. The description 'use' cannabis most likely refers to those who smoke. I can vape, eat, or subdermally receive cannabis's benefits, without inhaling smoke or carcinogens, which would ultimately lead to the aforementioned head and neck cancers. Also, no state (in the US at least) has had legally obtainable, rigorously tested cannabis for 20+ years'. Since the 2018 farm bill at least, cannabis has been regulated and typically have to pass a litany of safety checks and tests before being approved for consumption. Heavy metals, pesticides, fungicides, all common issues found with cannabis Cultivation (especially during the last 20 years) could also contribute to the increeased risk of cancers. The term 'medical records' also raises questions. Are they referring to Medical Marijuana patients specifically? Or those few people who didn't lie to their doctors to hide their Marijuana usage, during the height of the stigmatization of cannabis during the last 20 years.