Adenocarcinoma in situ of the lung is also a cancer, but it is only the earliest type of cancer and is the lowest level of cancer in the pathological analysis of lung cancer. Moreover, most patients with adenocarcinoma in situ of the lung do not have any symptoms in the early stage and are usually found to have this cancer only when they have a physical examination. In the early stage, the lung lesion can be removed surgically and the surrounding lymph nodes can be removed to avoid residual cancer cells. The cure rate of early adenocarcinoma in situ is relatively high and chemotherapy is not necessary, only regular observation and medical checkups are needed to prevent the disease from becoming more serious.