Prognosis is a prediction about how a disease will unfold. Will it improve, worsen, or stay stable? How long might the patient live? What is the likely response to treatment? These are the questions prognosis tries to answer.

Doctors build prognoses from statistics, clinical experience, and the specifics of the patient's case. A cancer prognosis might include five-year survival rates. A heart failure prognosis might estimate one-year mortality risk. These numbers are population averages. They describe a group, not an individual.

What shapes a prognosis

• Stage and grade of the disease.
• Patient age and overall health.
• Response to previous treatments.
• Genetic and molecular markers.
• Access to care and social support.

Prognosis is not destiny. Some patients beat the odds. Others decline faster than expected. Doctors deliver prognoses with uncertainty because medicine is not deterministic. A good prognosis conversation includes the range of possibilities, the factors that could change the course, and what the patient values most. It is one of the hardest conversations in medicine, and one of the most important.