Complete remission in acute promyelocytic leukemia despite persistence of
abnormal bone marrow promyelocytes during induction therapy: experience in
34 patients
RM Stone, M Maguire, MA Goldberg, JH Antin, DS Rosenthal and RJ Mayer
Division of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
02115.
Thirty-four patients with acute promyelocytic leukemia (APL) (median age 37
years, range 20 to 69 years) received induction treatment between 1974 and
1985 with cytosine arabinoside (ara-C) and an anthracycline. Bone marrow
hypercellularity was present at the time of diagnosis in all patients,
although the median peripheral leukocyte count was 2,600/microL. A second
course of induction therapy consisting of further ara-C and anthracycline
was initiated 15 days after the start of treatment if bone marrow
hypocellularity could not be documented. Karyotypic analysis of bone marrow
blasts was performed on 15 of 34 patients; 11 of 15 had abnormalities in
chromosomes 15 and/or 17. Twenty-nine of 34 (85%) patients had laboratory
evidence of disseminated intravascular coagulopathy. Of the 29 patients
surviving 14 days, 24 (83%) received a second course of induction therapy.
Complete remission was achieved in 25 of 34 (74%) patients, with four of 25
(16%) requiring one course of induction chemotherapy and 21 of 25 (84%)
receiving two courses. Bone marrow specimens obtained 15 days after the
start of therapy from the 25 patients who eventually attained complete
remission showed the continued presence of dysplastic promyelocytes in 21
cases; three specimens were technically inadequate and only one was truly
devoid of promyelocytes. Seventeen of 25 (68%) patients still had
persistence of abnormal bone marrow promyelocytes seven or more days after
the second course of therapy. Patients in complete remission received
various forms of postremission therapy. Ten of the 25 (40%) completely
responding patients remain alive in continuous complete remission. Neither
the absence of bone marrow hypocellularity nor the persistence of
dysplastic promyelocytes during induction exerted any influence on the
probability for survival. These findings confirm and extend prior reports
that complete remission in APL, in contrast to other subtypes of acute
nonlymphocytic leukemia (ANLL), can frequently be achieved without bone
marrow aplasia. Whether this observation signifies that complete remission
in APL is due to leukemic cell differentiation or selective cytotoxicity is
unknown. The absence of therapy-induced bone marrow hypoplasia in APL is
not an absolute indication of induction failure or a poor ultimate
prognosis.
Volume 71,
Issue 3,
pp. 690-696,
03/01/1988
Copyright © 1988 by The American Society of Hematology
