I am 58y i was diagnosed with lung cancer/adenocarcinoma at stage 4 (where it spread in both lungs). i am currently taking erlotinib. is it curable?

Yur Oncologist can h: The most helpful person to you in your battle with lung cancer is your oncologist. You should have a frank conversation with him/her asking questions about prognosis/ long term outlook for you. Not knowing whether your tumor is responding to Erlotinib or not, i may not be able to do justice to address prognosis of your lung cancer. The outcomes do vary among patients with same type/stage of cancer.

Prolonged remission: Is possible , but you have to ask your oncologist , who has knowledge , skills to treat you , to give the best possible treatments available and the only one who is assessing response to the therapy , good luck.

I am afraid not: Stage IV disease is treatable, but unfortunately it is incurable disease. Please discuss further with your oncologist.