There is no specific time for a 3mm lung nodule to turn into cancer, it depends on many factors such as the individual’s physical condition, the speed of disease progression and the effect of treatment. Most of the lung nodules are caused by inflammation and generally belong to benign lesions. 3mm lung nodules that are solid and solitary have a low probability of malignancy and belong to low-risk nodules, with only 0.2% of possibility of cancerous transformation. If there are no infections or any uncomfortable symptoms, it is recommended to do regular CT follow-up to observe the changes of the nodules, which generally will not be transformed into cancer very soon, or even will not be transformed into cancer for the rest of one’s life. If the size of the lung nodule increases to more than 5mm and its nature is glassy, it is necessary to be alert to the deterioration of the nodule, and it is necessary to do lung enhancement CT and tissue puncture biopsy to determine the diagnosis, and it is necessary to treat the nodule actively after the diagnosis is confirmed. If there are signs of nodule enlargement, or symptoms such as cough, chest pain, chest tightness, dyspnea and so on, you need to consult a doctor in time. In daily life, you need to pay attention to maintain a good state of mind, do not need to be overly nervous, and actively cooperate with the doctor’s treatment, which will help the condition to recover.