RESUMO
OBJECTIVE: To investigate the optimal time of monitoring minimal residual disease (MRD) for predicting survival and prognosis in children with T-cell acute lymphoblastic leukemia (T-ALL) after treated by CCLG-ALL2008 chemotherapy. METHODS: 96 children with T-ALL receiving CCLG-ALL2008 chemotherapy treated in our hospital from January 2015 to January 2020 were retrospectively summarized. The follow-up time was 9.0-65.0 months, with a median of 43.5 months. Kaplan-Meier survival curve was used to detect the overall event-free survival (EFS) and overall survival (OS) of the patients. The clinical data, MRD levels after 15 d, 33 d and 90 d chemotherapy between EFS group and relapse group, as well as OS group and death group were compared by using univariate analysis. Multivariate Logistic regression analysis was used to screen the main risk factors affecting EFS and OS of the patients. The patients were divided into low, moderate and high-risk according to the MRD level after 15 d, 33 d and 90 d, the differences of EFS and OS between each groups were compared again. RESULTS: By the end of follow-up, 50 patients recurred and other 46 patients non-recurred; 40 patients died and 56 patients survived, the EFS was (49.5±6.3)% and OS was (61.5±5.9)%. Univariate analysis showed that the initial WBC count in EFS group (n=46) was significantly lower than that in relapse group (n=50), and MRD levels after 33 d and 90 d were significantly less also (P<0.05). Prednisone response in OS group (n=56) was better than that in death group (n=40), and central nerve invasion rate was lower, MRD level after 33 and 90 d were lower (P<0.05). Logistic regression analysis showed that MRD level after 90 d was the main risk factor affecting EFS of the patients; prednisone reaction, central nerve invasion and MRD level after 90 d were the main risk factors affecting OS of the patients (P<0.05). There were no differences of EFS or OS between the groups according to the MRD levels after 15 and 33 d (P>0.05), however for 90 d, EFS and OS of the patients in high-risk group were significantly lower than those in medium-risk group, and those in medium-risk group were lower than those in low-risk group (P<0.05). CONCLUSION: The MRD level after 90 days CCLG-ALL2008 chemotherapy may be the best time to predict the survival and prognosis in T-ALL children.