Hi,
I too had lichen planus before being diagnosed with SCC (also gingival). My doctor told me that approximately 3-5 per cent of people with lichen planus will have it progress to SCC. There are different degrees of lichen planus and the most troublesome is the 'erosive' kind, the most acute.

If you do a search of the OCF site for 'oral lichen planus', you will find a wealth of information.

Hope this helps, Sheldon