The likely outcome of a disease, called the “prognosis,” varies in patients with PV. Each patient’s prognostic risk factors are evaluated individually. In people with PV, median survival approaches or exceeds 20 years. Some people may survive longer after diagnosis, perhaps achieving a near-normal life expectancy. It is important to know that outcome data can show how groups of people with PV responded to treatment, but cannot determine how any one person will respond. For these reasons, patients are advised to discuss survival information with their doctors.