I did not have tongue cancer......my lesion was on the gums of my upper jaw and spread to the hard palate.....but I, too, had adult braces and am prone to aphthous ulcers and injure easily. I am not convinced that there is nothing to the "repeated irritation" theory of causation. I smoked 37 years ago....never drank enough to count...have NO cancer in my family.....tested neg. for HPV.