Effect of complete remission and responses less than complete remission on survival in acute myeloid leukemia: a combined Eastern Cooperative Oncology Group, Southwest Oncology Group, and M. D. Anderson Cancer Center Study.
OBJECTIVE
It is known that complete remission (CR) prolongs survival in acute myeloid leukemia (AML). In 2003, less stringent response categories were introduced, most notably CR with incomplete platelet recovery (CRp). Although the significance of CRp for survival remains unclear, reports of AML trials frequently combine CR with CRp rather than considering CR as a separate entity.


METHODS
This practice led us to retrospectively examine the effect of CR on outcome in newly diagnosed AML, by using data from 6,283 patients treated on Eastern Cooperative Oncology Group (ECOG) and Southwest Oncology Group (SWOG) protocols or at M. D. Anderson Cancer Center. This effect was then contrasted with the effect of CRp in the M. D. Anderson Cancer Center cohort.


RESULTS
At least 94% of patients receiving cytarabine-based therapy and surviving for more than 3 or 5 years achieved a CR with either initial or salvage therapy; limited data suggest the same for patients receiving initial therapies that did not contain cytarabine. Patients with CR were more likely to live beyond 3 or 5 years than patients with CRp. The likelihood of achieving a CR rather than CRp was greater for patients with AML who had better prognosis. After adjustment for covariates, the relapse-free survival of patients achieving CR was longer than that of patients achieving CRp, whereas patients with CRp survived longer than those with resistant disease.


CONCLUSIONS
Our data indicate that CR is of unique clinical significance and should be reported as separate response in trials of newly diagnosed AML. Nonetheless, our findings validate CRp as a clinically meaningful response.
Clinical Research Division and Southwest Oncology Group Statistical Center, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA. rwalter@fhcrc.org
Roland B
RB
Walter
Hagop M
HM
Kantarjian
Xuelin
X
Huang
Sherry A
SA
Pierce
Zhuoxin
Z
Sun
Holly M
HM
Gundacker
Farhad
F
Ravandi
Stefan H
SH
Faderl
Martin S
MS
Tallman
Frederick R
FR
Appelbaum
Elihu H
EH
Estey
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002986:Clinical Trials as Topic; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy / Q000235:genetics / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012074:Remission Induction; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome