Objective: To probe into the reduction and withdrawal of 6-mercaptopurinein (6-MP) in children with acute lymphoblastic leukemia (ALL) during maintenance therapy and its effects on long-term prognosis. Methods: From Jan. 2011 to Jan. 2016

totally 120 children with ALL admitted into Zhengzhou Children’s Hospital were extracted to be divided into the standard dose treatment group

half dose and above treatment group

half dose and below treatment group and drug withdrawal group according to different doses of 6-MP. The incidence of side effects and clinical efficacy after treatment of two years were compared. Results: Except for the significant increase of recurrence rate in the drug withdrawal group (P<0.05)

there was no significant difference in the disease-free survival rate

recurrence rate and mortality of the other three groups (P>0.05). After the reduction of white blood cells and withdrawal of 6-MP

all children had rare side effects such as rash

gastrointestinal reactions

hepatotoxicity and severe infection. Conclusion: According to the peripheral white blood cells and neutrophils count

the reduction of 6-MP does not affect the long-term prognosis of the children with ALL

and there are no significant clinical adverse drug reactions

but drug withdrawal can increase the long-term recurrence rate of the children.