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Shorter Maintenance Therapy in Childhood Acute Lymphoblastic Leukemia: The Experience of the Prospective, Randomized
Silvia R Brandalise1, Marcos B Viana2, Vitória R P Pinheiro1
1Boldrini Children's Center , Campinas , Brazil.
Insights
Reducing maintenance therapy for childhood acute lymphoblastic leukemia (ALL) by six months did not affect event-free survival (EFS) rates. This shorter duration offers similar outcomes to the standard 24-month regimen in ALL treatment.
Area of Science:
- Pediatric Oncology
- Hematology
- Clinical Trials
Background:
- Maintenance therapy is crucial for childhood acute lymphoblastic leukemia (ALL) treatment, typically lasting two years.
- Standard maintenance involves weekly methotrexate and daily 6-mercaptopurine (6MP).
- Reducing therapy duration may alleviate burdens, especially for children in low-income countries.
Purpose of the Study:
- To prospectively compare event-free survival (EFS) rates in children with ALL undergoing 18-month versus 24-month maintenance therapy.
- To evaluate the impact of reduced maintenance duration on treatment outcomes.
Main Methods:
- A prospective study involving 853 eligible children with ALL (<18 years) treated under the GBTLI ALL-93 protocol.
- Patients were randomized to receive either 18-month (n=421) or 24-month (n=432) maintenance therapy.
- Risk classification was based on age, leukocyte count, and extra-medullary involvement; intention-to-treat analysis was used.
Main Results:
- The overall 15-year event-free survival (EFS) was 66.1%.
- No significant difference in EFS was observed between the 18-month (65.8%) and 24-month (66.3%) maintenance groups (p=0.79).
- Stratified analyses by adverse prognostic factors (age, high WBC) also showed no difference between the regimens.
Conclusions:
- A six-month reduction in maintenance therapy duration for childhood ALL, as per the GBTLI ALL-93 protocol, yields outcomes comparable to the standard 24-month regimen.
- This shorter duration is a viable option without compromising overall treatment success.
Aim:
Maintenance therapy is an important phase of the childhood ALL treatment, requiring 2-year long therapy adherence of the patients and families. Weekly methotrexate with daily 6-mercaptopurine (6MP) constitutes the backbone of maintenance therapy. Reduction in the maintenance therapy could overweight problems related with poverty of children with ALL living in limited-income countries (LIC).
Objective:
To compare, prospectively, the EFS rates of children with ALL treated according to two maintenance regimens: 18 vs. 24 months duration.
Materials And Methods:
From October 1993 to September 1999, 867 consecutive untreated ALL patients <18 years of age were treated according to the Brazilian Cooperative Group for Childhood ALL Treatment (GBTLI) ALL-93 protocol. Risk classification was based exclusively on patient's age and leukocyte count (NCI risk group) and clinical extra medullary involvement of the disease. Data were analyzed by the intention-to-treat approach.
Results:
Fourteen patients (1.6%) were excluded: wrong diagnosis (n = 7) and previous corticosteroid (n = 7). Of the 853 eligible patients, 421 were randomly allocated, at study enrollment, to receive 18-month (group 1) and 432 to receive 24-month (group 2) maintenance therapy. Complete remission rate was achieved in 96% of the patients (817/853). Twenty-eight patients (3.4%) died during the induction phase. Thirty-four patients (4.0%) were lost to follow-up. The overall EFS was 66.1 ± 1.7% at 15 years. No difference was seen according to maintenance: EFS15y was 65.8 ± 2.3% (group 1) and 66.3 ± 2.3% (group 2; p = 0.79). No difference between regimens was detected after stratifying the analyses according to factors associated with adverse prognosis in this study (age group <1 year or >10 years and high WBC at diagnosis). Overall death in remission rate was 6.85% (56 patients). Deaths during maintenance were 13 in group 1 and 12 in group 2, all due to infection. Over 15 years of follow-up, two patients both from group 2 presented a second malignancy (Hodgkin's disease and thyroid carcinoma) after 8.3 and 11 years off therapy, respectively.
Conclusion:
Six-month reduction of maintenance therapy in ALL children treated according to the GBTLI ALL-93 protocol provided the same overall outcome as 2-year duration regimen.
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