Malignant tumors of the lungs do not grow at a uniform rate. Generally when a ground glass nodule appears in the lung, consider early adenocarcinoma. If the diameter of the nodule is less than 1cm, it usually grows slowly, sometimes there is no big change in 5-6 years. However, when the diameter of ground-glass nodule exceeds 1cm, the multiplication speed will accelerate, and sometimes the nodule can develop into 2-3 centimeters in about half a year, and it is likely to be transformed into invasive adenocarcinoma, therefore, when the lesion reaches 1cm, it should be given surgical treatment in time.