Background: In 2017, institutional carboplatin dosing guidelines were developed to standardise carboplatin prescribing practices for doses of Area-Under-Curve (AUC) greater or equal to 4. The objective of this study was to evaluate the impact of the current carboplatin dosing protocol upon carboplatin dose adjustments, toxicity and tolerability in patients with cancer.
Methods: This is a retrospective study where data was collected pre-implementation (1st October 2016 to 31st March 2017) and post- implementation (1st October 2017 to 31st March 2018) of the carboplatin dosing guideline. Patients who started first cycle carboplatin with dose AUC 4 or above during the specified periods were identified from the electronic oncology treatment database. Medical records were reviewed to determine demographics, cancer diagnosis, estimated glomerular filtration rate (GFR), measured GFR (by 51CR-EDTA clearance), protocol compliance, dose adjustments and reasons for dose adjustments.
Results: Data was collected for 81 patients with 300 doses during the pre-intervention period and 79 patients with 305 doses during the post-intervention period. Of these, 219 (pre-intervention) and 226 (post-intervention) repeat doses of carboplatin were assessed for dose adjustments based on changes to patients’ renal function and/or weight. Dose adjustments relating to change in serum creatinine and/or weight decreased from 13.9% to 5.0% (P < 0.05). All dose differences greater than 20% from cycle 1 were corrected in compliance with protocol. The rates of inappropriate dose adjustment reduced from 8.0% to 2.9% (P = 0.069). At least one dose reduction or delay due to clinical toxicity occurred in 26 patients (34%) pre-intervention and 28 patients (35%) post-intervention. The median and 80th percentile ranges reduced from 33 and 69 different doses (pre-intervention) to 9 and 19 (post-intervention) respectively.
Conclusion: Implementation of an institutional carboplatin dosing protocol for patients with cancer reduced the burden of unnecessary dose adjustments, and was not associated with increased toxicity.