Myeloid sarcoma is associated with superior event-free survival and overall survival compared with acute myeloid leukemia

BACKGROUND. It is unknown whether patients with nonleukemic myeloid sarcoma (MS) and those with acute myeloid leukemia (AML) have similar responses to anti-AML treatment. In the current study, the authors addressed this question by matching MS patients with analogous AML patients and comparing their clinical outcomes. METHODS. Twenty-three consecutive patients with MS and 1720 consecutive patients with AML were identified who presented at The University of Texas M. D. Anderson Cancer Center from 1990 to 2004. All AML patients and 16 MS patients received cytarabine plus idarubicin or fludarabine as induction remission therapy. Treated MS patients and AML patients were matched according to cytogenetics, age, Zubrod performance status, and time of treatment. Event-free survival (EPS) and overall survival (OS) were compared using Kaplan-Meier analyses. RESULTS. Complete response rates were 69% in patients with MS and 57% in patients with AML (P = .45). The respective 2-year EFS and OS rates were 32% and 18% (P = .08) and 43% and 29% (P = .11). Matches were identified for 14 MS patients who were paired repeatedly with 91 AML patients to produce 94 matches (3 AML patients were matched twice). EFS was longer in 56 MS pair mates, shorter in 26 pair mates, and similar in 12 pair mates (P = .01; Fisher exact test). OS analyses yielded similar results. CONCLUSIONS. Anti-AML therapy was highly effective in patients with nonleukemic MS. The results from this study emphasize the need to treat patients who have nonleukemic MS with AML-type therapy.