My FIL was just diagnosed with stage 4 lung cancer.
This may explain it better than i can . I have dealt with patients many times with different stages of Lung CA. Stage 4 isn't the best to be diagnosed with .
Stage 0 carcinoma in situ.
Stage I cancers are localized to one part of the body.
Stage II cancers are locally advanced.
Stage III cancers are also locally advanced. Whether a cancer is designated as Stage II or Stage III can depend on the specific type of cancer; for example, in Hodgkin's Disease, Stage II indicates affected lymph nodes on only one side of the diaphragm, whereas Stage III indicates affected lymph nodes above and below the diaphragm. The specific criteria for Stages II and III therefore differ according to diagnosis.
(Stage IV cancers have often metastasized, or spread to other organs or throughout the body. )