There is no accurate clinical data to show how long it generally takes for a medium differentiated cancer to metastasize, but it is known that medium differentiated cancer is a medium malignant cancer, and its metastasis depends on the type of cancer, treatment method and other factors. The differentiation degree of cancer cells is divided into three levels: high, medium and low. Generally, the lower the differentiation degree, the higher the malignancy, indicating the faster the growth of cancer cells and the shorter the time for metastasis to occur. In case of moderately differentiated lung adenocarcinoma, the time to metastasis is usually shorter and more likely than that of squamous lung cancer. Some moderately differentiated cancers may metastasize faster and may take less time after treatment with surgery, usually due to the increased rate of cancer cells entering the blood and lymphatic circulation as a result of surgical resection, thus accelerating the metastasis of cancer, but there are no clinical statistics on how long it takes for metastasis to occur. However, there are no clinical statistics on how long it takes for metastasis to occur. It is not possible to generalize how long it takes for metastasis to occur in middle fractionated cancer, and patients are advised to follow the guidance of doctors and take active and effective treatment to reduce the chance of metastasis.