My 66 yr old mother was diagnosed a year ago with stage 4 lung cancer and colon cancer. She has had two types of chemo and now has been put on Tarceva a month ago. She has not had any rash, but has had bad diarrhea. Does anyone know how long this will last? She eats very little because she never knows what will start the diarrhea again. Otherwise she feels fine. Any info on this would be helpful. Thanks!!