Staging
It is important to know that while stages are an important guide to treatment and prognosis, they are certainly not the whole picture. There can be many individual situations within these stage groupings. For instance, if a patient with kidney cancer has only one metastasis and it can be removed surgically, and it's been several years since he had his kidney out, the prognosis is much better than if he had many metastases which appeared just after surgery to remove the kidney. Sometimes the treatment depends on just where metastases are located. There are, for instance, specialized methods for treating bone metastases and brain metastases. If a new treatment becomes available, some sub-group of patients within a certain stage may suddenly have a much better prognosis. Finally, it's important to keep in mind that there is considerable variation in outcome for every type and stage of cancer. A prognosis associated with a cancer stage is only a general guide, not a prediction, a sentence, or a guarantee.
If you do choose to do serious research into the technical literature for your cancer, it will be useful to understand how cancer is classified and staged in general, as well as to understand the staging system for your particular cancer.
Cancer staging systems describe how far cancer has spread anatomically and attempt to put patients with similar prognosis and treatment in the same staging group. Since prognosis and treatment depend quite a bit on the stage, you can see how important it is to know what stage you have! At the same time other factors, including your general health, your own preference, and the results of biochemical tests on your cancer cells will contribute to determining the prognosis and treatment. So while the stage is important it is not everything.