AGNOGENIC MYELOID METAPLASIA - NATURAL HISTORY AND TREATMENT

At the Mayo Clinic from 1960 to 1965, 137 patients with agnogenic myeloid metaplasia were observed. Forty-eight of the 137 patients had asymptomatic agnogenic myeloid metaplasia and did not require therapy; yet, these patients had only a 58% probability of surviving 50 months after the diagnosis was made. Eighty-nine patients with symptomatic agnogenic myeloid metaplasia were treated with various medical regimens and had a 52% probability of survival for 50 months. The group of patients treated medically with adrenal hormones or radiation, or both, in addition to androgens, busulfan, and transfusions did not demonstrate any significant increase or decrease in probability of survival as compared to the group of patients who did not have severe hemolytic anemia or mechanical symptoms related to huge spleen. This finding suggests that indolent disease, even without severe hemolysis or mechanical compression by a huge spleen, represents a serious problem. A highly selected group of 16 patients who underwent splenectomy showed an 80% probability of survival 30 months after the procedure. This was significant when compared to 54% probability of survival at 30 months of patients treated exclusively medically. In the splenectomy group a drop to 50% probability of survival occurred at 36 months. Adequate determination of the probability of survival after splenectomy at 48 months as compared to an exclusively medically treated group will require further observation over a longer period.