Serum Phosphorus Level in ALL Children - Case Control Study

Background – Acute lymphoblastic leukemia (ALL) is the most prevalent childhood leukemia and metabolic changes with electrolyte abnormalities are commonly seen during the course of the disease and therapy. Phosphorus changes in the serum have been reported in children with ALL, especially during the occurrence of TLS and metabolic changes induced by chemotherapy.
Objective: To compare the serum phosphorus levels of ALL children with healthy controls and to determine the association of the serum phosphorus level with age, gender, FAB classification, chemotherapy cycles and disease duration.
Design: 50 children with ALL (cases) and 30 healthy children (controls) aged 1-16 years were included in this case control study. Serum phosphorus was determined and compared among groups. To assess associations with demographic and clinical parameters, such as gender, age groups, FAB classification (L1, L2, L3), number of chemotherapy cycles and disease duration, statistical analysis was conducted.
Results: The study included 35 boys (70%) and 15 girls (30%). FAB classification showed L1 in 43 patients (86%), L2 in 1 patient (2%), and L3 in 6 patients (12%). Mean serum phosphorus was 4.4±0.8 mg/dL in cases versus 4.1±0.6 mg/dL in controls (P=0.109). No statistically significant differences were found by gender (boys 4.47±0.84 vs girls 4.15±0.70 mg/dL, P=0.729), age groups (1-8 years 4.56±0.70 vs 9-16 years 4.19±0.89 mg/dL, P=0.113), FAB type (L1 4.29±0.79, L2 4.20, L3 5.02±0.80 mg/dL, P=0.115), chemotherapy cycles (<10 cycles 4.59±0.73 vs ≥10 cycles 4.27±0.83 mg/dL, P=0.191), or disease duration (P=0.083).
Conclusions: Mean serum phosphorus levels were slightly higher in children with ALL than in controls but the difference was not statistically significant. The lack of clinical associations indicates that, in stable ALL patients, outside of the period of acute tumor lysis, there is relative preservation of phosphorus homeostasis. But it is important to keep an eye out during certain time of a person's life, such as when they are undergoing chemotherapy and diagnosis.