Patients with ground glass nodules in the lungs are often a little confused, “Dr. Hsieh, why, when you have diagnosed me with early stage adenocarcinoma in situ, why do you still let me follow up instead of letting me just have surgery to remove it? My nodule is also large in diameter, why don’t you let me have surgery? We need to balance four aspects: the first aspect is the malignancy of the tumor (whether the tumor has the ability to metastasize and the probability of future enlargement), the second aspect is the degree of trauma of the surgery (the degree of damage to the patient’s lung function), and the third aspect is the patient’s own physical condition and the timing of the surgery. (1) If the tumor is invasive lung cancer, then this is the type that kills people (such as CT value of -200Hu or -300Hu, capable of distant metastasis), in this case, as long as the physique can tolerate it, no matter lobectomy, lung segment resection, or even double lobectomy, it is worthwhile, and it is worthwhile to pay as much as we can. (2) If the tumor is a suspected adenocarcinoma in situ (usually CT value of -600~-500Hu), if the location of the lesion is deep, located at the junction of several lung segments, or in the medial 1/3 of the lung, radical resection, lobectomy or combined lung segment resection is needed, especially for a low density ground glass nodule, then in this case, it is not cost effective to do the surgery, such a surgery is relatively more traumatic In this case, it is not advisable to do surgery, such a surgery is relatively invasive, and this tumor is only brushing up its existence at present, and does not have the ability of metastasis or recurrence (at the same time, the probability of enlargement in the short term is not high), in this case, you can follow up and observe first. (3) If the tumor is suspected, between in situ adenocarcinoma and microinfiltrating adenocarcinoma (CT value around -500Hu, no metastatic ability), it is also possible to consider following up and observing first. (4) If the tumor is suspected and between microinvasive adenocarcinoma to invasive adenocarcinoma (CT value around -350 to -400Hu), lobectomy is acceptable. This is the appropriate timing. 2. Timing of surgery (1) If you are not yet married, or have not yet found a job, if the lesion is only suspected adenocarcinoma in situ, or the degree of adenocarcinoma in situ to the junction of microinvasive adenocarcinoma, it is possible to consider follow-up observation first. In order not to affect the future marriage process. (2) If you are planning to have a child, if the lesion is suspected to be adenocarcinoma in situ, you can consider having a child first and then come to the observation to decide whether to operate or not. Evidence and experience so far show that estrogen and progesterone during pregnancy have little effect on ground glass nodules. (3) Patients of advanced age over 80 years old or in poorer health, if in situ or microinvasive adenocarcinoma is suspected, it is also recommended to follow up and observe first.