Outcome of children with T cell acute lymphoblastic leukemia treated with Chinese Children Leukemia Group acute lymphoblastic leukemia (CCLG-ALL) 2008 protocol

Abstract

Objective: To evaluate the efficacy of the Chinese Children's Leukemia Group (CCLG) acute lymphoblastic leukemia (ALL) 2008 protocol (CCLG-ALL 2008) in the treatment of children's T-cell acute lymphoblastic leukemia (T-ALL). Methods: Clinical characteristics and outcomes of 84 newly diagnosed T-ALL children (63 males and 21 females) treated with CCLG-ALL 2008 protocol from April 2008 to April 2015 in the Department of Pediatric Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences were analyzed retrospectively. Kaplan-Meier analysis was used to evaluate the overall survival (OS) and event free survival (EFS), and COX regression was used to evaluate the influencing factors of OS and EFS. Results: (1) Baseline data: 84 children were included, 56 cases (67%) of children were younger than 10 years old. Patients whose white blood cell count≥50×10(9)/L ranked 70% (59/84). Karyotype: 58% (49/84) with normal karyotype, 10% (8/84) with abnormality of chromosome 11, 8%(7/84) with abnormality of chromosome 9, 2%(2/84) with abnormality in both chromosome 11 and chromosome 9, 8% (7/84) with other complex karyotypes. Fusion gene: 33%(28/84) were SIL-TAL1 positive. The patients were grouped by CCLG-ALL 2008 risk score, 40% (34/84) were in the intermediate risk group and 60% (50/84) in the high risk group. (2) Treatment efficacy: 84 cases were followed up until May 30, 2018. The follow-up time was 42.0 (0.3-120.0) months. The sensitivity rate of prednisone treatment was 56% (47/84); the complete response (CR) rate after the induction therapy of vincristine+daunoblastina+L-asparaginase+dexamethasone (VDLD)(d 33) was 88% (74/84); the total CR rate after VDLD induction combined with cyclophosphamide+cytarabine+6-mercaptopurine (CAM) treatment (d80) was 94% (79/84); the recurrence rate was 24% (20/84). Among the 20 recurrent cases, there were 13 cases (65%) with ultra-early recurrence (within 18 months after diagnosis), 6 cases (30%) with early recurrence (18 to 36 months after diagnosis); 1 patient (5%) with late recurrence (over 36 months after diagnosis). During the follow-up period, twenty-eight children (33%) died (22 cases with recurrence or suspending treatment without remission, 2 cases with infection, 1 case of sudden death in chemotherapy, 1 patient failed in transplantation, 1 patient with severe cirrhosis, and 1 patient with unknown cause). (3) Kaplan-Meier analysis: the 5-year OS and EFS of the 84 children were (63±6)% and (60±6)% respectively. (4) Efficacy in different risk groups: prednisone sensitivity rates in the two different risk groups were 100% (34/34) and 26% (13/50), respectively (χ(2)=3.237, P<0.05). The CR rates at the end of VDLD induction therapy (d 33) were 100% (34/34) and 80% (40/50), respectively (χ(2)=2.767, P<0.05). The recurrence rate of children in the two groups was 12% (4/34) and 32% (16/50), respectively (χ(2)=4.245, P<0.05).The mortality rates of the two groups were 21% (7/34) and 42% (21/50), respectively (χ(2)=3.198, P<0.05). Kaplan-Meier analysis showed that the 5-year OS of the two groups were (77±7)% and (53±8)%; and the 5-year EFS of the two groups were (75±8)% and (49±8)% (χ(2)=4.235, 3.875, both P<0.05) . (5) COX multivariate regression analysis showed that the classification of risk according to CCLG-ALL 2008 was an important factor influencing the prognosis of children with T-ALL (OR=3.313, 95% CI 1.165-9.422, P=0.025). Conclusions: The results of the risk group treatment according to the CCLG-ALL 2008 protocol showed that the long-term survival of children with middle risk was significantly better than that of children at high risk.