Does surgery improve life expectancy for patients with stage 3 lung cancer?

Depends on type: Stage III is divided into stage iiia and iiib. Surgery is an option for patients with stage iiia. Surgery may increase survival in conjunction with preoperative chemotherapy +/- radiation in patients who do not require a pneumonectomy (removal of whole lung) and patients with small lymph nodes (non-bulky) and cancer in lymph nodes in one area or "single station" only.

If so, not much: Albain et al tried to show that surgery improved survival in operable iiia, but there was no statistical benefit. The subset that got just a lobe removed possible benefited, but would need a larger study to prove. Those that had the entire lung removed actually faired worse. For most patients, it is not the thing that makes a difference, but response to chemo/rt signals benefit.