Among pediatric patients with acute lymphoblastic leukemia (ALL), peripheral blood blast and platelet counts are together highly predictive of clinical and survival outcomes, according to research published in Medicine.
ALL accounts for nearly one-fifth of all pediatric cancers, and although survival rates have greatly improved in the past several decades, around 20% of patients will relapse. Despite therapeutic improvements, this still carries a poor prognosis.
Several hematological and biological features have been identified that aid in prediction of relapse and risk stratification. A frequently used variable is the presence of minimal residual disease (MRD), which has repeatedly been shown to be highly prognostically significant, although MRD monitoring is not always possible.
Other independent variables with suggested prognostic relevance include time to platelet recovery or platelet count post–induction therapy and peripheral blood blast counts, though these variables have not previously been evaluated as a combined prognostic marker. For this study, researchers evaluated the prognostic value of this combined marker among pediatric patients with ALL.
Between 2011 and 2015, 419 pediatric patients were enrolled. The age range was 0 to 14 years, 219 patients (52.3%) were male, and 205 patients (48.9%) had standard-risk disease. At day 33, a total of 245 patients (58.8%) had MRD status of less than 0.01%.
The median follow-up was 41 months (range, 0-80). In the entire cohort, the 3-year event-free survival (EFS) and overall survival (OS) rates were 82.2% and 87.3%, respectively.
At day 8, compared with blast counts of less than 0.1 x 109/L, counts of at least 0.1 x 109/L predicted greater relapse risk (hazard ratio, 3.412; P <.001). At day 33, platelet counts of at least 100 x 109/L predicted superior relapse risk (hazard ratio, 0.403; P =.003). Platelet counts on day 33 were similarly predictive of OS.
Univariate and multivariate analysis suggested, furthermore, that low blast counts on day 8, coupled with high platelet counts on day 33, were predictive of both EFS and OS. The combination predictive marker correlated well with risk stratification based on MRD status.
“Based on data from the current study, the combination of low blast count on day 8 and high platelet count on day 33 was found to be independently associated with a superior outcome in patients with ALL,” the authors wrote. “Therefore, the combined use of blast and platelet counts during and after induction treatment for childhood ALL was a strong candidate prognostic factor for the improvement of risk stratification when MRD was not available.”
Dai Q, Shi R, Zhang G, et al. Combined use of peripheral blood blast count and platelet count during and after induction therapy to predict prognosis in children with acute lymphoblastic leukemia. Medicine (Baltimore). 2021;100(15):e25548. doi:10.1097/MD.0000000000025548