Introduction
Systemic chemotherapy, incorporating high-dose methotrexate (HD MTX), is an important component of care for patients under the age of 40 with osteosarcoma. Delivery of methotrexate requires inpatient admission to facilitate monitoring of MTX clearance, provide hydration, urinary alkalinisation and folinic acid administration. Standard practice is to measure MTX levels every 24 hours until below 0.10μmol/L, in order to be cleared for discharge.
Aim
To assess the impact of an earlier standardised MTX level at 60 hours on overall length of stay (LOS) compared to the standard 24-hourly level.
Methods
A retrospective cohort study at a tertiary sarcoma centre between 21/5/2019 and 18/11/2021 was designed to identify the difference in LOS following the institution’s implementation of a 60-hour MTX level. A two-sample t-test was conducted between pre- and post-implementation of the 60-hour MTX level LOS.
Results
Fifteen patients with a total of 112 admissions were eligible for analysis. The average LOS in the pre-60-hour MTX level LOS group was 83.5 hours (n=45), with the post-implementation average LOS being 76.5 hours (n=67). The majority (85%, 57/67) of the post-implementation group were eligible for 60-hour testing, of which 84% (48/57) had reached the required level of 0.10μmol/L and were able to be discharged (average LOS 70.9 hours). A two-sample t-test showed that there was a statistically significant difference (p-value <0.0001) between the pre-implementation group, and post-implementation group who had cleared their methotrexate.
Conclusion
The introduction of a 60-hour MTX level demonstrated a statistically significant decrease in the LOS by more than 12 hours in eligible patients, with the majority of patients (71%, 48/67) able to be discharged after the 60-hour MTX level.