TREATMENT OF ACUTE PROMYELOCYTIC LEUKEMIA WITH ALL-TRANS-RETINOIC ACID - A 5-YEAR EXPERIENCE

From January 1986 to April 1991, 107 consecutive patients with acute p romyelocytic leukemia (APL) were treated with retinoic acid (RA) at an oral dose of 45-60mg/m2/d, alone or in combination with chemotherapy. In 91 cases treated with RA alone, 74 (81.3%) achieved complete remis sion (CR). The CR rate was 75% in 16 cases treated with combined thera py. Among 50 patients closely followed for a median of 36 months (4-60 ), 10 received RA as continuation therapy (Group A), 10 received chemo therapy (Group B) and 30 were treated with RA and chemotherapy alterna tely in regular sequence (Group C). The mean survival time was 8.4, 9. 7 and 21.6 months, respectively, for the 29 cases who died. The surviv al probability was higher in Group C than in Group A and B (P<0.01). R A did not provoke or aggravate DIC, it did not cause marrow hypoplasia or aplasia. The side effects were relatively mild as compared with ch emotherapy. CFU-GM markedly reduced before treatment was restored to n ormal level after CR, while the result for L-CFU was reversed. In 40 c ases examined for in vitro induction of differentiation, 39 responders were culminating in CR. Aberrant karyotype t (15; 17) was positive in all 47 cases examined prior to the treatment. It disappeared in all o f the 20 cases studied after achieving CR, and reappeared in 3 cases f ollowing relapse. The best regimen to maintain a longer CR duration an d survival time in this study was to use RA and chemotherapy alternate ly as continuation therapy.