When we say that a person is cured of their cancer, the implication is that the cancer will never come back. Practically speaking, you are cured of your cancer when your illness is not measurable by blood tests or scans or identified on physical examination for a prolonged period of time. Most but not all cancer doctors (oncologists) would agree with that statement. If those criteria are met for a very short time, then you are said to be "NED" -- that is, you have "no evidence of disease." If you remain "NED" for years, you are considered cured. Surgeons use the word cure for certain cancers if there is a "wide excision" and "clean margins" at the time of surgery. "Wide excision" means that all the visible tumor was removed along with some normal tissue around it.  "Clean margins" means that, when this tumor with the apparent normal tissue surrounding the tumor was checked under a microscope, no cancer was seen around the edges.

How many years you need to be free of your cancer depends on the cancer you had and the oncologist you ask. For example, if you had a cancer at the tip of a polyp in your colon, and five years later you have no measurable disease, almost all oncologists would say you are cured. If your cancer was a type that can recur later (such as certain breast cancers), and your cancer at the outset was widespread, almost all oncologists would be reluctant to say you are cured, even 10 years later.

The best person to tell you if you are cured is your physician.