The question is can a lung CT be cancerous after 3 months, probably asking if a lung nodule will be cancerous if you wait 3 months to review it. There is a certain period of time for some lungs to become cancerous, usually called the tumor doubling time, and the tumor doubling time usually takes about 3-4 months if it is very fast, and 2-3 years if it is slow is possible. Therefore, doctors usually choose the shortest interval of 3 months as a review interval, even if there is a possibility of cancer in the future, usually 3 months will not delay the disease. Therefore, if there is a high suspicion of cancer, the doctor will ask the patient to undergo a review once every 3 months to prevent a missed diagnosis or misdiagnosis.