Prognosis
The expected course of a disease: how likely it is to be cured, how long a person is likely to live, and how they are likely to feel. Always an estimate based on groups of similar patients, never a prediction for one person.
Prognosis in cancer depends chiefly on stage, then on grade, histology, molecular subtype, and the patient's fitness and age; it is expressed as survival rates (the proportion alive at five years) or median survival, drawn from registries and trials of past patients treated with past therapies, so it lags behind current treatment. Prognostic biomarkers (Ki-67, Oncotype DX recurrence score, ctDNA after surgery) refine the estimate and, importantly, help decide who needs more treatment and who can be spared it. Distinguishing prognostic from predictive is essential: a prognostic marker says how the disease will behave whatever you do, a predictive marker says whether a specific drug will help.