Count Recovery in AML Patients Achieving a Complete Response.

Abstract 2062

Poster Board II-39

AML is typically defined as “de novo” or “secondary”, the latter referring to patients diagnosed only after persistent blood count abnormalities (AHD) or after prior “chemotherapy” (PCT) for other illnesses. Patients with secondary AML may have a different bone marrow microenvironment leading to prolonged neutrophil and platelet recovery times following induction chemotherapy. Accordingly, we compared time from start of chemotherapy to neutrophil recovery (>1,000/μl) and platelet recovery (>100,000/μl) in 424 patients who achieved a complete response (CR) following treatment with ara-C-containing induction therapy at MD Anderson Hospital from 1995 to 2008. We divided the 424 patients as follows: (1) no AHD, no PCT (236 patients); (2) AHD, no PCT (131 patients); (3) PCT, no AHD (28 patients); and (4) AHD and PCT (29 patients). Because time to recovery may also be influenced by cytogenetics and age we subdivided patients in each of the four groups according to age (< vs. ≥ 60) and cytogenetics (normal vs. complex or -5/-7). Despite very differing CR rates, time to neutrophil recovery in patients achieving CR while statistically longer in PCT patients (p=0.05) was from a medical standpoint essentially uninfluenced by AHD and PCT status (table, median delays 2 days with PCT). Platelet recovery was affected by such status (p<0.001) being delayed by a median of 6-8 days in patients who had received PCT. Age had no effect on time to neutrophil (p=0.42) or platelet (p=0.23) recovery, while complex or -5/-7 cytogenetics had a statistically significant (p=0.002 neutrophils, 0.009 platelets) but medically insignificant (median delays of 2 days) effect on recovery time. There was no interaction between age or cytogenetics and AHD or PCT status. A similar analysis in patients who do not achieve CR would be of interest, but might be confounded by the difficulty in distinguishing between the effects of chemotherapy and those of residual AML on count recovery. Our data suggest that older patients, patients with complex or -5/-7 cytogenetics, and patients with secondary AML should not be excluded from clinical trials because of concern about prolonged time to count recovery.