study if tarceva blocks cells for oral cancer

i have had tongue cancer twice in the past 18 years and now have leukoplakia (pre-cancer) on my gum and tongue for the past 5 years.  My doctor wants me to go into a (EPOC) study trial taking the drug Tarceva (or sugar pill) which they are testing to see if it can make the cells in my mouth normal and be stabilized.  I recently had a genetic marker study and was told I have a 50 - 70% change of getting oral cancer again within the next three years (from the numbers). I have DNA damage.  My doctor feels this study is the "cutting Edge" and I will be monitored very closely for the next year while I'm taking "tarceva". (or sugar pill).  I am worried about taking tarceva since I do not have cancer now and feel the side effects can be bad.  But if I don't do the study what are my options? Does anyone have any advise out there for me.  I'm going crazy trying to make a desision.

Rosemary