My mom has been diagnosed with stage 4 lung cancer in both her lungs, lymph nodes & around the lining of the heart what is life expectancy ? she's 50

Variable: It's not possible to cure her advanced cancer. Try to make the most of every precious minute. My deepest condolences to her and you.

Unfortunate: Stage 4 lung cancer survival steadily improving with new therapies but not quick enough. It also depends type of cell age , sex females do better and general health . Non small cell 50% survive 8 months , over all less than 18% 5 yr survival. Give all the support and help you can along with family,make her comfortable try traditional and new regimes .