Long-Term Outcomes of Modified St Jude Children's Research Hospital Total Therapy XIIIB and XV Protocols for Thai Children With Acute Lymphoblastic Leukemia.

Background: We studied long-term outcomes and prognostic features of Thai children with acute lymphoblastic leukemia treated with modified St Jude Children's Research Hospital (SJCRH) protocols.

Patients And Methods: Pediatric patients newly diagnosed with acute lymphoblastic leukemia were included. From 1997 to 2003, the first group received modified Total Therapy XIIIB (previous protocol). From 2004 to 2014, the latter had modified Total Therapy XV (current protocol).

Results: In 250 patients, the event-free survival rates (± standard error) of the previous protocol (n = 95) were 82.8 ± 3.9%, 81.7 ± 4.0%, and 81.7 ± 4.0% at 5, 10, and 15 years, respectively; current protocol event-free survival rates (n = 155) were 84 ± 3.0%, 80.8 ± 3.4%, and 80.8 ± 3.4%, respectively. Previous protocol overall survival rates for the same years were 89.2 ± 3.2%, 84.8 ± 3.8%, and 84.8 ± 3.8%, and for the current protocol were 90 ± 2.5%, 86.9 ± 3.2%, and 83.7 ± 4.4%. Previous protocol relapses were 10.5% (10 patients), with 7 having isolated hematologic and 3 isolated/combined central nervous system relapses. Current protocol relapses were 9.7% (15 patients), with 7 having isolated hematologic, 6 isolated/combined central nervous system, and 2 extramedullary relapses. Patients with leukocyte counts over 100 × 10/L and who had disease classified as high risk had worse event-free survival using the previous protocol. However, only initial leukocyte counts of ≥ 100 × 10/L predicted adverse outcomes under the current protocol. Minimal residual disease positivity was a prognostic factor of worse overall survival only for previous protocol patients.

Conclusion: Favorable outcomes of childhood acute lymphoblastic leukemia occurred using adapted SJCRH protocols, perhaps because of multidisciplinary care teams and improved parent advocacy. Inferior outcomes might be prevented by addressing predictive factors to ameliorate monitoring and care.