The prognosis (the likely outcome of the disease) varies widely in patients with myelofibrosis (MF). Each patient's prognostic risk factors are evaluated differently. A very large proportion of symptom-free patients remain stable for years without needing treatment.
While the median survival for people with MF is about 5 years, people younger than 55 and with good prognostic factors have a median survival of 11 years. However, some people may survive for decades following a diagnosis. It is important to know that outcome data can show how groups of people with MF 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.
Although there is no staging system for MF, the International Prognostic Scoring System (IPSS), uses the following five risk factors for estimating survival from the time of diagnosis:
- Age - 65 years or older
- Anemia - Hemoglobin level lower than 10 grams per deciliter (g/dL)
- Symptoms - Such as fever, night sweats or weight loss
- Leukocytosis - An elevated white cell count of above 25,000/µl
- Circulating blood blast cells - At least 1 percent.
According to the IPSS, patients without any of these adverse features, excluding age, have a median survival of more than ten years. The presence of any three of the above adverse features reduces the median survival to two years. However, recent long-term studies of ruxolitinib (Jakafi®) suggest that it can improve survival times in patients with MF for several years.