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[Stratification therapy in patients with acute promyelocytic leukemia after a complete remission by all-trans retinoic acid].

OBJECTIVE
To explore an efficacious protocol for the patients with acute promyelocytic leukemia (APL) after a complete remission (CR) by all-trans retinoic acid (ATRA).


METHODS
A total of 32 APL patients with an induction of CR by ATRA at our hospital from January 2000 to October 2007 received conventional standard chemotherapy as a consolidation regimen. Stratified according to age, those under 50 years old received an intermediate dose of cytarabine(IDAra-C)and over 50 years old non-IDAra-C regimen. Maintenance regimen: all patients received ATRA, arsenic trioxide (As2O3) and 6-mercaptopurine (6-MP) + methotrexate (MTX) alternately and sequentially for 3 years. The efficacy and side effects of these chemotherapies were observed.


RESULTS
The median follow-up was 72 (40 - 124) months. The 5-year disease-free survival (DFS) rates of under 50 years old and over 50 years old were 94.7% and 92.3% respectively. The difference was statistically insignificant (P > 0.05). One patient relapsed after a consolidation therapy and so did another on a maintenance regimen. Thirty patients achieved a constant CR. And 16 of 30 patients completed chemotherapy beyond 5 years and survived disease-free. The 5-year DFS rate of 32 patients was 93.8%.


CONCLUSION
After the achievement of CR with ATRA, all APL patients have a higher rate of DFS after stratification. The side effects are generally mild. Thus a stratification therapy is both feasible and efficacious.