So why would throat cancer be rare in.my 20s?

Takes time to develp: Throat cancer associated with smoking/alcoholism takes time to develop. 1st your normal throat cells change to different cells than they are supposed to be due to toxic effects of smoking. Over time those different cells can mutate & become cancer cells. Once they become cancer cells, throat cancer is very aggressive. So it is less likely do get throat cancer in your 20s. Same if have acid reflux.

Cumulative Effect: See oral surgeon or ENT doc if you have any of these symptoms: Persistent mouth sore, persistent mouth pain, a lump or thickening in the cheek, a white/red patch on the gums, tongue, tonsil, or lining of the mouth, a sore throat, hoarseness or feeling that something is caught in the throat that does not go away, difficulty swallowing/chewing.