INTRODUCTION
Acute lymphoblastic leukemia (ALL) is the most common malignant disease diagnosed in children, with a prevalence of up to 26 % of all childhood malignant diseases in patients under the age of 15 1. While the survival rate in 1960 was only a few percent, outcome was improved successively with the development of combination chemotherapy in successive cooperative clinical trials, resulting in long term survival in over 90% of children today 2. This progress is based on treatment optimization trials with risk-adapted treatment, on leukemia biology and response to treatment. Furthermore, supportive care was improved, in particular prevention and treatment of severe infections. Additionally, treatment was intensified such as including consolidation with stem cell transplantations (SCT)3. However, 70 % of children in the world live in low income countries, where the development of effective leukemia therapy remains very challenging, given the limitations in infrastructure, resources, trained personnel and thus access to care, with outcomes that are often still lower than 35% 4. Furthermore, it is also estimated that less than 60% of children worldwide even have access to cancer treatment 5. There is a lot of data available about childhood ALL in Europe and in the USA, but comparable data from most Asian countries, especially from low and lower-middle income countries like Cambodia, is still scarce even though it is estimated that there are 54 000 new ALL cases per year in Asia6. The health care system in Cambodia has only limited resources (Yeoh et al., 2014) and gaining access to a hospital is often difficult financially and geographically. For 30 years the Kantha Bopha Foundation has provided free health care in 5 hospitals in two locations to an estimated 85 % of all Cambodian children. Based on the development of available expertise, including laboratories for infectiology and hematology with the possibility to perform whole blood transfusions and a dedicated staff, ALL therapy was introduced based on a treatment protocol with a moderate reduction of treatment intensity for all patients 7 in one central location in Phnom Penh. Here, we analyze the results of this treatment regimen over a period of three years with sufficient follow-up time as a basis for further development for pediatric oncology care.