Have had white area on tongue for abt 1 year. no changes. do i have to treat leukoplakia or can i leave it? is an annual oral cancer screening enuf?

Brush biopsy: Could be trauma or something else. You can get a brush biopsy and find out what it is. Easy and painless and then you will know.

Have it removed: Given that you are not a smoker the risk of tongue cancer is less than that of a smoker. That being said, leukoplakia is a change of the oral mucosa that is pre-cancerous. Removal of a small tongue lesion is a fairly easy procedure and will remove the lesion and allow a biopsy at the same time. It would be best to have it removed.

Get it checked: I'd recommend you defer to recommendation of a oral surgeon that knows his stuff. They'd prob want biopsy of some sort before feeling comfortable to watch it. I'd take lots of pics.

Exam, biopsy: Leukoplakia can be a premalignant lesion. See oral surgeon or ENT doc for exam, possible biopsy.