Long-term (5 to 20 years) Evolution of nongrafted aplastic anemias. The Cooperative Group for the Study of Aplastic and Refractory Anemias. In the presence of aplastic anemia (AA), therapeutic choices should be determined while taking into account not only changes for immediate improvement, but also both the risks for late-occurring complications and the following quality of life. We report here data concerning a long-term clinical survey (5 to 18 years with a median of 12 years) including 156 nongrafted patients receiving androgen therapy; all patients were alive more than 5 years after diagnosis (40% of patients included at time of diagnosis in our multicentric analysis). Between the 5th and the 13th year follow-up, 21 patients died of various causes either related to AA or to its treatment: 12 of infection or hemorrhage secondary to pancytopenia (6 relapses and 6 that had never been improved; 2 with paroxysmal nocturnal hemoglobinuria [PNH]); 5 of leukemia; 1 of a non-Hodgkin's lymphoma; 2 of late side effects following transfusion (1 acquired immunodeficiency syndrome and 1 chronic B hepatitis); and a single case of myocardial infarction (the latter could possibly result of androgen therapy). Thirteen patients in total developed PNH (among which 10 had clinical symptoms including 2 deaths, and 3 exhibited only biologic abnormalities). Few long-term side effects of androgens could be noticed. Adult height was normal in patients treated during childhood and so was young women's fertility. No malignant hepatoma occurred. This survey allows the recording of late spontaneous hematologic improvement (between 5 and 10 years of evolution). This occurred in 50% of patients that had remained cytopenic 5 years after diagnosis. Although bone marrow stem cell concentration remained abnormal after 10 years of evolution. 85% of patients had a normal red blood cell count, 80% a normal polymorphonuclear count, and 66% a normal platelet count. All patients who did not show late complications had an excellent quality of life. 