How quickly does lung cancer spread?

Very variable: This varies with cancer type and route of spread among other factors. At the time of diagnosis, small cell lung cancer is more often already spread to other organs. Non-small cell cancer can stay as small lung nodules for a couple of years before picking up speed. Spreading via the blood vessels can be sometimes faster than spread through the lymph nodes.

Depends: Depends on the kind of cancer and the individual patient. In general, all lung cancers have better prognosis if diagnosed and treated earlier.

Depends: Depends on the type of lung cancer, the location, and the person's overall immune status.