If the annual risk of cancer from oral lichen planus is about 0.2%, how the lifetime risk is just about 1%...after only 5 years the risk is already 1%?

Statistics: I suspect the numbers may go something like this: of all the lichen planus patients observed in any one year .2% of them are cancer and in a person who has lichen planus, 1% of them turn into cancer over a lifetime. The bottom line is that if someone has oral lichen planus, it needs to be monitored by a doctor on a regular basis. I would also avoid tobacco use and alcohol.

Low risk: Either way, the risk is very low. You should have regular dental exams to detect any changes. There are easy to administer test to determine cancer or pre-cancer changes.