ID #1002 Hematologic Toxicity during Proton Radiation: a Review of Weekly CBC Results at a Single Center
Casey Miller, Hillary Camardo, Danille Fohl, Jessica Davis, Trent Hummel, Aaron Mochizuki, Natasha Pillay Smiley, Richard Graham, Scott Raskin, Andrew Frankart, Luke Pater, Peter de BlankAbstract
Introduction
Hematologic toxicity is a known adverse event of craniospinal irradiation. However, the effects of acute hematologic toxicity in pediatric patients with brain tumors receiving proton radiation is less known. The frequency of lab draws can increase patients’ procedural-related anxiety and may increase the risk of bloodstream infections. We examined results of weekly complete blood counts (CBCs) to evaluate the use of weekly lab draws.
Methods
Previously non-irradiated pediatric patients with primary tumors of the brain and spine receiving proton therapy between August 2016 and Dec 2026 were evaluated. Weekly CBCs with differential were reviewed according to Common Terminology for Adverse Events (CTCAE), version 5.
Results
Among 392 patients treated with primary proton radiation to brain and/or spine, 2065 CBCs were reviewed (mean 5.3 CBCs/patient). Mean hemoglobin (+standard deviation) was 11.4 + 1.8g/dL. CTCAE grade 3 anemia (hemoglobin<8g/dL) was identified in 33/2065 CBCs (1.6%). Mean platelet count was 225,000 + 96/microL. CTCAE grade 3 thrombocytopenia (platelet<50/000/microL) was seen in 17/1400 CBCs (1.2%). Mean absolute neutrophil count was 2990 + 2290cells/microL. CTCAE grade 4 neutropenia (<500/microL) was found in 46/2059 (2.2%).
Conclusion/Relevance
Significant hematologic toxicity requiring transfusion or neutropenic precautions are rare during primary radiation for CNS tumors, accounting for only 1.2%-2.2% of weekly CBCs. Further analysis in this dataset will examine timing of hematologic toxicities and transfusions to determine when laboratory evaluations may be most useful. Weekly CBC surveillance may not be useful for most primary pediatric brain tumors.