Because you have lung cancer, it is very important that you do not smoke, and it is helpful if you avoid being around people who are smoking.
Smoking can cause more cancer to develop.
Exposure to smoke can also increase the lung damage you have already suffered. Eating right is also very important. Adding lots of fresh fruits and vegetables is recommended. And, rest is very important to help your body to heal. It has been shown that vitamins A and E in excess of the recommended daily requirements do not help and, in fact, may be harmful.