How are you? I have a quick question about Tarceva usage. My dad was diagnosed with Stage IV NSCLC about two years ago. He has tumor on the left lung and spread to the bones of the full upper body and part of the lower body. He was put on Tarceva since this summer. And it worked really well on him. The blood count of cancerous cells and the size of the tumor have decreased dramatically. My mom has concerns about continuous use of Tarceva. When can my dad stop using Tarceva? I've heard that if on Tarceva the patient has to use it for the rest of the life unless it stops working. Is that true? If not, can he stop using Tarceva if the cancer is totally under control? Any help will be deeply appreciated from my whole family.