A cure is a substance or procedure that ends a medical condition, such as a
medication
A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and re ...
, a
surgical operation
Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...
, a change in lifestyle or even a philosophical mindset that helps end a person's sufferings; or the state of being healed, or cured. The medical condition could be a
disease
A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...
,
mental illness
A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...
,
genetic disorder
A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...
, or simply a condition a person considers socially undesirable, such as
baldness
Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scarrin ...
or lack of breast tissue.
An incurable disease may or may not be a
terminal illness
Terminal illness or end-stage disease is a disease that cannot be cured or adequately treated and is expected to result in the death of the patient. This term is more commonly used for progressive diseases such as cancer, dementia or advanced he ...
; conversely, a curable illness can still result in the patient's death.
The proportion of people with a disease that are cured by a given treatment, called the cure fraction or cure rate, is determined by comparing
disease-free survival
Survival rate is a part of survival analysis. It is the proportion of people in a study or treatment group still alive at a given period of time after diagnosis. It is a method of describing prognosis in certain disease conditions, and can be use ...
of treated people against a matched control group that never had the disease.
Another way of determining the cure fraction and/or "cure time" is by measuring when the hazard rate in a diseased group of individuals returns to the hazard rate measured in the general population.
Inherent in the idea of a cure is the permanent end to the specific instance of the disease. When a person has the
common cold
The common cold or the cold is a viral infectious disease of the upper respiratory tract that primarily affects the respiratory mucosa of the nose, throat, sinuses, and larynx. Signs and symptoms may appear fewer than two days after exposu ...
, and then recovers from it, the person is said to be ''cured'', even though the person might someday catch another cold. Conversely, a person that has successfully managed a disease, such as
diabetes mellitus
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...
, so that it produces no undesirable symptoms for the moment, but without actually permanently ending it, is not cured.
Related concepts, whose meaning can differ, include ''response'', ''remission'' and ''recovery''.
Statistical model
In complex diseases, such as cancer, researchers rely on statistical comparisons of
disease-free survival
Survival rate is a part of survival analysis. It is the proportion of people in a study or treatment group still alive at a given period of time after diagnosis. It is a method of describing prognosis in certain disease conditions, and can be use ...
(DFS) of patients against matched, healthy control groups. This logically rigorous approach essentially equates indefinite remission with cure.
The comparison is usually made through the
Kaplan-Meier estimator approach.
The simplest cure rate model was published by
Joseph Berkson
Joseph Berkson (14 May 1899 – 12 September 1982) was trained as a physicist (BSc 1920 College of City of New York, M.A., 1922, Columbia), physician (M.D., 1927, Johns Hopkins), and statistician (Dr.Sc., 1928, Johns Hopkins).O'Fallon WM (1998). " ...
and
Robert P. Gage
The name Robert is an ancient Germanic given name, from Proto-Germanic "fame" and "bright" (''Hrōþiberhtaz''). Compare Old Dutch ''Robrecht'' and Old High German ''Hrodebert'' (a compound of '' Hruod'' ( non, Hróðr) "fame, glory, honou ...
in 1952.
In this model, the survival at any given time is equal to those that are cured plus those that are not cured, but who have not yet died or, in the case of diseases that feature asymptomatic remissions, have not yet re-developed signs and symptoms of the disease. When all of the non-cured people have died or re-developed the disease, only the permanently cured members of the population will remain, and the DFS curve will be perfectly flat. The earliest point in time that the curve goes flat is the point at which all remaining disease-free survivors are declared to be permanently cured. If the curve never goes flat, then the disease is formally considered incurable (with the existing treatments).
The
Berkson and Gage equation Berkson is a surname. Notable people with the surname include:
*Joseph Berkson (1899–1982), American physicist
**Berkson's paradox (or Berkson's fallacy)
**Berkson error model
*Bill Berkson
William Craig Berkson (August 30, 1939 – June 16, ...
is