It is impossible to judge the stage of lung cancer just by the fact that the lung nodule is larger than 4cm. Because there are two possibilities of benign and malignant for lung nodules larger than 4cm, to determine the nature of 4cm lung nodules, it is necessary to conduct biopsy of the nodules for pathological examination, and based on the pathological results, to diagnose whether the lung nodules are lung cancers or benign lung nodules. For pathologically diagnosed lung cancer nodules, the size of the nodule alone cannot determine the specific stage of lung cancer, and a number of imaging tests, such as chest and abdominal CT, brain magnetic resonance, whole-body bone scan, etc., are needed to evaluate the stage of lung cancer of the patient. Clinically, only when the stage of lung cancer is clear, patients can choose anti-tumor treatment measures such as surgery, radiotherapy, targeted therapy and so on according to their physique and other different conditions, so patients need to actively consult doctors for clarification.