A prognosis (from the Greek for "forseeing") is a determination of how a diagnosed disease will progress in a given patient. A terminal patient is one in whom the given disease is incurable and will eventually result in the patient's death. Up until the 19th century, giving a prognosis was often the only thing a physician could do once a diagnosis was reached. It was only in the late 19th century that the focus of the medical profession shifted to actually trying to cure a disease rather than just predicting its course.
A proper prognosis will include:
- How long the disease is likely to persist;
- What life functions of the patient will likely to be impaired in the patient;
- What the likely course of the disease will be, including such outcomes as progressive decline, intermittent regular crisis, or sudden-onset crisis;
- Whether the patient's symptoms will regress for a period of time before they get worse;
- The survival rate for a certain percentage of persons (the 50/50 rate) or the rate of survival over a given period of time (such as a five-year survival rate).
In many cases, a disease's prognosis can only be determined correctly in a large population of patients and the individual prognosis is inherently unpredictable. This is the case for most forms of terminal cancer.