A cure is the end of a medical condition; the substance or procedure that ends the medical condition, such as a medication, a surgical operation, a change in lifestyle, or even a philosophical mindset that helps end a person’s sufferings. It may also refer to the state of being healed, or cured. A remission is a temporary end to the medical signs and symptoms of an incurable disease. A disease is said to be incurable if there is always a chance of the patient relapsing, no matter how long the patient has been in remission. 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 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, 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, 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.