There are quite a few stages of cancer and it is ranked in accordance to severity. The reasons why it is important that cancer stage will be identified properly. The rate of survival will be compromised it the diagnosis of cancer stage is wrong. The stage is classified from 0-4. The least severe is 0 and four is the most dangerous. . Moreover, there is another system to classify the stages. There is Tumor, Node Metastasis. Some doctors may give oppose on their prognosis. So it should be best to make sure and know how their approach on treatment may differ. To learn more, read Stages of Cancer and The Importance for Your Treatment