The simple answer to this question is living a long life. But the medical community uses other terminology to describe various states of disease along the way toward cure. For patients who begin their treatment at Memorial Sloan Kettering, most “events” — e.g. relapse, serious side effects, development of a secondary cancer — usually occur within three years of diagnosis. By five years after diagnosis, few relapses are seen, although there are occasional recurrences past five years.
When we talk about the effectiveness of a treatment or the state of a patient’s disease, there are a number of frequently used terms that may come up.
Remission or No Evidence of Disease (NED)
These are terms that indicate that the signs and symptoms of neuroblastoma are no longer present. However, it is possible that neuroblastoma cells may continue to exist in the body at a level at which current testing methods cannot detect. These terms mean the same thing as Complete Remission.
Complete Remission (CR)
This is a term that indicates that no signs, symptoms, or other evidence of neuroblastoma are present. As for remission and NED, a patient considered to be in complete remission may still have cancer cells in the body because current testing methods are not able to detect individual cells or very small clusters of cells. This term means the same thing as Remission and No Evidence of Disease.
This is a term that indicates that although no clear signs, symptoms, or evidence of disease remains, tests continue to show scar tissue or other abnormalities that make it impossible to classify the case as Complete Remission.
Partial Remission or Partial Response (PR)
These are terms that indicate that the size of the primary tumor or the extent of neuroblastoma cells in the body has decreased by more than 50 percent, but evidence of disease remains.
Very Good Partial Remission (VGPR)
This is a related technical term that indicates that the patient has only minimal tumor mass remaining at the primary site and no evidence of metastatic disease except for improving abnormalities shown on a bone scan (though MIBG
tests are negative).
Mixed Response (MR)
This is a term that indicates that there has been some reduction in the size of the primary tumor or the extent of neuroblastoma cells in the body, but the response is less than what would be considered partial remission. This term can be confusing because, despite the usual meaning of the word “mixed,” it does not refer to a situation in which there is response in some sites but progression in other sites. In fact, to qualify as Mixed Response, disease progression cannot have occurred anywhere in the body.
This is a term that simply indicates that the patient is alive.
Progression-Free Survival (PFS) and Relapse-Free Survival (RFS)
These are terms that indicate that over some specified period of time the patient has survived and there has been no progression or relapse in his or her disease.
Event-Free Survival (EFS)
This is also a technical term that indicates that over some specified period of time the patient has survived and there has been no serious event. The term “event” does not have the same meaning for all doctors and at all treatment centers, so patients are encouraged to ask their doctors for specific details on how they interpret these terms. For example, while treatment-related leukemia is generally accepted as an event, removal of a vital organ like a kidney is not.