To the Editor.—
The article by Bortin and Rimm (p 1245) reporting the results of the Marrow Transplant Registry indicates that two (4% ) of 57 patients with end-stage acute myelogenous leukemia (AML) are living after marrow transplantation. In comparing the survival curves for the Registry cases with the Seattle cases, there was no significant difference, even though a rather clear separation between the curves emerged. Statistical significance depends strongly on sample size, and the number of longterm survivors in both series of patients is small. This should not obscure the fact that there are some long-term disease-free survivors in a group of patients where no other therapeutic approach is known to produce long-term survivors.In the Seattle series of 46 patients, 17 cases were in remission 100 days after transplantation and eight were in remission at one year—a result that compares favorably with experimental chemotherapy for this type of patient.