If it was completely removed, it won't become a stage 4. Stage 4 cancer is the stage at which it has spread from the original organ into other parts of the body, or metasticized. If it returns, it will not be the same tumor. A good reference for you to see is cancer.gov. It's the website for the American Cancer Society, and it lists all types of cancer, all treatments, and the prognosis for each. You need to find out exactly what type of cancer it was (there are many types, sometimes many different kinds for each organ), and research that one.