Higher urinary excretion of inorganic phosphate during early induction chemotherapy predicts a good prognosis in childhood acute leukemia.

The rapidity of response to induction therapy is emerging as an important prognostic factor in children with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Urine inorganic phosphate (IP) and uric acid (UA) may increase in patients with acute leukemia who undergo their induction chemotherapy, owing to the breakdown of tumor cells. The crystallization of UA or calcium phosphate in renal tubules can result in acute tumor lysis syndrome (ATLS). Some reports indicate that patients who experience ATLS have a better prognosis than those who do not. We investigated the relationship between urinary IP and UA excretion and treatment outcome in children with acute leukemia. Participants included 93 patients with ALL and 31 patients with AML. Urine samples were collected and measured for the first 3 days of induction chemotherapy. Among patients with ALL, urinary IP excretion was significantly higher in patients without relapse than in those with relapse and correlated with long-term outcome. Among patients with AML, urinary IP excretion was significantly higher in patients without induction failure (IF) than those with IF. We propose that higher urinary IP excretion could be a useful prognostic marker for determining favorable outcomes in patients with acute leukemia.