Low-differentiated lung adenocarcinoma represents its degree of differentiation, and does not represent whether it is advanced or not, they are different concepts. Lung adenocarcinoma is one of the common pathological types of lung cancer, which can be caused by smoking, gene mutation and other factors. According to the degree of differentiation of cancer cells, it can be classified into three grades: high, medium and low, and the higher the grade, the higher the degree of malignancy and the worse the prognosis. The staging of middle and low differentiated lung cancer needs to be evaluated according to the primary tumor, the degree of lymph node metastasis and whether distant metastasis occurs. Usually, the later the stage, the more complicated the condition and the worse the prognosis. Late stage mostly means that the cancer has already developed distant metastasis. It is recommended that patients go to regular hospitals to get a clear diagnosis and specific stage, and receive standardized treatment as soon as possible.