My dad had lung cancer surgery last year and they got it all. He did not do treatment. Now it is in the brain. How long could he live?

D/w his oncologist. Sorry for your dad's condition. Treatment, and prognosis would depend obviously on the stage, however, the type of lung cancer, whether he would do treatment now, what treatment, and how is the response to therapy would also affect the prognosis. In general, based on studies, people with stage 4 lung cancer -on average- with treatment could live for 12-15 months. It would be much less without tx.
Lung cancer. 1. If there are multiple spots in brain, whole brain radiation 2. If solitary lesion, surgical resection or cyberknife.3 need staging pet scan for rest of body 4.With brain mets expected average survival is 6-9 months.5. The tumor subtype and molecular profile can help tailor systemic therapy.