Remission is either the reduction or disappearance of the signs and symptoms of a disease. The term may also be used to refer to the period during which this diminution occurs. A remission may be considered a partial remission or a complete remission. For example, a partial remission for cancer may be defined as a 50% or greater reduction in the measurable parameters of tumor growth as may be found on physical examination, radiologic study, or by biomarker levels from a blood or urine test. Each disease or even clinical trial can have its own definition of a partial remission.
A complete remission, also called a full remission, is a total disappearance of the manifestations of a disease. A person whose condition is in complete remission might be considered cured or recovered, notwithstanding the possibility of a relapse, i.e. the reappearance of a disease. In cancer-treatment, doctors usually avoid the term "cured" and instead prefer the term "no evidence of disease" or NED to refer to a complete remission of cancer, which does not necessarily mean that the cancer won't come back.