Background: All-trans-retinoic acid(ATRA) induces complete remission(CR) in the great majority of patients with PML/RARα-positive acute promyelocytic leukemia(APL).
However, it is associated with a rapid rise in leukocytes in one third to half the patients, with potentially fatal “ATRA syndrome”. Furthermore, most of the patients
relapse with maintenance therapy using ATRA alone or low-dose chemotherapy. In this study, we have analyzed the outcome for APL patients who were treated with ATRA
alone or combined with low-dose chemotherapy followed by postremission chemotherapy in Chonnam University Hospital from April 1993 to December 1997.
Methods: Sixteen patients with newly diagnosed APL were eligible to analysis. Patients received 45mg/m 2 ATRA until CR occurred. If initial WBC were above 5,000/μL, low-dose chemotherapy was concomitantly given, and if during the ATRA therapy WBC were above 5,000/μL by day 5 or 10,000/μL by day 10, or 15,000/μL by day 15, low-dose chemotherapy was added. Four polychemotherapy cycles or allogeneic bone marrow transplantation were given as postremission therapy.
Results: Median age was 34 years(range, 17 to 67). Of 16 APL patients, 15(93.8%) achieved CR and 1(6.2%) died of intracerebral hemorrhage. After a median follow-up of
11.5 months(range,0 to 47), the Kaplan-Meier estimated overall survival(OS) rate was 87.1±8.6% at 3 year, the event-free survival(EFS) rate was 87.1±8.6%, 58.0±24.4% and 29.0±23.9% at 1 year, 2 year and 3 year, and the disease-free survival(DFS) rate was 92.9±6.9%, 69.6±20.7% and 46.4±23.5% at 1 year, 2 year and 3 year, respectively.
Conclusion: The present study suggests that ATRA with or without low-dose chemotherapy followed by postremission chemotherapy is a well-tolerated and effective regimen that is shown to improve the CR rate, reduce a early mortality rate and considerably prolong the overall survival in patients with newly diagnosed APL.

Keywords: All-trans retinoic acid(ATRA), Acute promyelocytic leukemia(APL), Chemotherapy,