Is there any treatment for stage 4 lung cancer?

Yes, but - - - -: Will likely be only palliative since the prognosis is usually poor for advanced cancer. Seek consultation with an Oncologist preferably in a Cancer treatment center.

Yes: You need to see the oncologist groups there is new therapies and immune therapies so depending on type there maybe some therapy to help improve quality box life

Stage IV: there is no cure at this stage. but there are many treatments and the goal is palliative( meaning improve the quality of life) or modest increase in the survival .

Yes: When stage 4 lung cancer develops most patients have been on chemotherapy including the platinum drugs. Some of the newer chemo is an old version employing liposomes which increases the activity of the drug such as employed with Abraxane. Now, especially with the more common form of disease, the adenocarcinomas, checkpoint inhibitors such as the anti PD1's have shown some excellent responses.

Yes indeed: Today's chemotherapy may produce an excellent or good remission. There is talk of survival for years. Radiation may help bone pain.