Tarceva has the best chance of working with an EGFR Mutation. But it can also work without in some people. There is a great deal of work being done on the Kras mutation because its so common in L/C . There are certain chemos that are more effective with KRAS.
The side effects of Tarceva are usually mild and to get it with Radiation gives the best outcome. If he responds to the Tarceva it can last for quite a while and there are numerous drugs in pipeline to counteract the resistance that eventually builds up in Tarceva.
Make sure you are getting treatment at a top line Lung cancer expert facility.
Also ask about clinical trials. So much is in the pipeline that holds real promise even for advance stage. I am posting some data now.