Background Tumour Lysis Syndrome (TLS) is an oncological emergency caused by the rapid lysis of tumour cells. One of the biochemical abnormalities seen is a high urate level; rasburicase, a recombinant urate oxidase, can therefore be employed in both prophylaxis and treatment. Studies show significant variability in treatment regimens; its use is based on guidelines, such as those from The British Committee for Standards in Haematology (BCSH). It also carries a small risk of haemolytic anaemia, especially in those with a G6PD deficiency.

Objectives This study aimed to evaluate rasburicase use within a PICU setting. We assessed whether our unit was following best practice in terms of treatment duration, drug dosage and frequency, and monitoring (both for treatment response and complications).

Methods This was a retrospective study of patients receiving treatment with rasburicase in our PICU from January 2015 to May 2020. Patients receiving rasburicase were identified using electronic prescribing records. Data concerning demographics, diagnosis, clinical condition, rasburicase administration, and monitoring was then obtained from Metavision and Orion Clinical Portal. TLS risk was determined retrospectively and children classed as either having High Risk Disease (HRD), Intermediate Risk Disease (IRD), or Low Risk Disease (LRD).

Results 21 patients receiving rasburicase were identified (18 with haematological malignancies, 3 with solid tumours). Data on ethnicity was available for 15/21 children, all of whom were Caucasian. Ages ranged from 9 weeks to 16 years. 5/21 had evidence of lab TLS, with 4 of these meeting the criteria for clinical TLS. 11 children were assessed to have HRD, 5 as having IRD, and 5 as having LRD. All children who had features of TLS were at high risk. 9/21 children (42.9%) received more than the 5–7 days treatment recommended by manufacturers and the BCSH, with a range from 1–21 days. Most children received 0.2 mg/kg doses with only one child receiving a dose of 2 mg/kg on one occasion. 3 children received twice daily dosing. One child died after only one dose of rasburicase; of the remainder, 100% received daily FBCs, LFTs, and U&Es while receiving rasburicase, while only 16/20 (80%) received daily urate levels to monitor response. No cases of haemolytic anaemia due to rasburicase therapy were documented, but 17/21 children required at least one red cell transfusion whilst a PICU inpatient. G6PD status was checked in only one of the children.

Conclusions Significant variability in use of rasburicase exists within our PICU. Duration of rasburicase treatment varies widely and several other practices outwith those recommended by current best practice were observed, such as its use in children at low risk of developing TLS, repeated treatment courses, twice daily doses, and a child who received a >0.2 mg/kg dose. Active monitoring for haemolytic anaemia outwith daily FBCs is limited and is complicated by the frequency of children requiring blood transfusions. Awareness of this as a serious complication in a small number of children may need to be raised.