Hyperleukocytosis occurs in 15-20% of all newly diagnosed acute myeloid leukemia patients and requires emergent treatment with leukapheresis or hydroxyurea when accompanied by signs or symptoms of leukostasis. Currently, there is no standardized hydroxyurea dosing strategy, although usual dosing ranges from 50 to 150 mg/kg/day, and prescribing patterns vary significantly among oncologists and institutions. In addition to other hematologic and dermatologic toxicities, the use of hydroxyurea may be associated with significant mucositis and mucositis-related pain. The purpose of this study was to compare mucositis-related pain between two different hydroxyurea dosing strategies in patients who received hydroxyurea for cytoreduction during induction. A retrospective chart review of adult patients with acute myeloid leukemia treated with chemotherapy at UNC Medical Center from April 2014 to April 2016 who received at least one dose of hydroxyurea for cytoreduction was conducted. This study compared the safety and toxicity profiles of hydroxyurea in patients who received high-dose hydroxyurea (≥75 mg/kg/day) versus low-dose hydroxyurea (<75 mg/kg/day). Safety and toxicity were evaluated based on indicators of mucositis and cumulative intravenous narcotic requirements following induction chemotherapy. Data collection included baseline demographics, mucositis risk factors, baseline laboratory values, hydroxyurea dosing, mucositis indicators, and pain indicators. A total of 55 patients were included in the study, 21 patients (38.2%) received the high-dose hydroxyurea dosing strategy. The high-dose hydroxyurea dosing strategy had a significantly higher white blood cell count at diagnosis, increased duration of hydroxyurea, and received a higher cumulative dose of hydroxyurea. Additionally, the high-dose hydroxyurea dosing strategy patients were associated with significantly more grade 3 or 4 mucositis requiring a formulation change (0% versus 28.6%, p = 0.002) and significantly higher cumulative intravenous narcotic requirements during induction (p = 0.019). No significant differences in baseline demographics or mucositis risk factors between dosing strategies were identified. The high-dose hydroxyurea dosing strategy patients had a significant increase in cumulative intravenous narcotic requirements and formulation changes, both common interventions made for the treatment of mucositis. Additional studies are needed to further elucidate the safety and toxicity profiles of hydroxyurea dosing strategies and to explore the correlation between total cumulative hydroxyurea dose and total cumulative narcotic requirements.
Keywords: Hydroxyurea; cytoreduction; hyperleukocytosis; mucositis.