Lung cancer of 4 centimeters cannot determine the stage of cancer. Lung cancer staging is based on TNM standard, tumor size is one of the aspects, and it is also necessary to look at lymphatic metastasis and distal organ metastasis for more accurate analysis, which means that only knowing the size of lung cancer of 4 centimeters can’t determine which stage it belongs to. If there is no lymph node or distal organ metastasis and proliferation for the time being, lung cancer of 4 centimeters is in T2N0M0 stage, that is, early stage; if there is lymph node metastasis but no distal organ metastasis, it is considered to be in middle stage; if there are lymph node and distal organ metastasis at the same time, it means that it enters into the advanced stage.