Poster Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2023

Carboplatin dosing - Impact of the eviQ ADDIKD Guidelines (#232)

Benjamin N Rao 1 2 , Kumaran Manivannan 3 , Phillip Parente 2 3 , Rachel Wong 2 3
  1. Eastern Health Clinical School, Deakin University School of Medicine, Melbourne, Victoria, Australia
  2. Department of Oncology, Eastern Health, Box Hill, Victoria, Australia
  3. Eastern Health Clinical School, Monash University, Melbourne, Victoria, Australia

Aim

Carboplatin chemotherapy doses have traditionally been calculated using the Cockcroft-Gault (CG) formula when direct GFR measurement is not available. The eviQ ADDIKD guidelines now recommend using the BSA-adjusted Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. We reviewed the potential impact of this change in a real-world setting.

 

Methods

This is a retrospective audit of patients receiving carboplatin-based chemotherapy regimens between January 2022 and January 2023. Baseline characteristics recorded included sex, height, weight, serum creatinine, treatment intent and single agent vs. combination regimen. Actual C1D1 carboplatin dose was compared to dose calculated using the CG and CKD-EPI formulae, accepting a 25mg variation. C1 treatment-related toxicity, including myelosuppression requiring dose modification was also recorded.

 

Results

163 patients were identified; mean age 63 years; 97 (60%) female. Treatment intent was curative in 60, palliative in 100 and unknown in 3 patients. 150 received carboplatin monotherapy and 13 combination regimens.

Compared to actual dose received, the CKD-EPI calculated carboplatin dose was within 25mg for 49 (30%), >25mg higher for 92 (57%) and >25mg less for 21 (13%) of patients. Compared to the CG calculated dose, the CKD-EPI carboplatin dose was within 25mg for 60 (37%), >25mg higher for 51 (32%) and >25mg less for 51 (32%) of patients.

Of the 34 patients experiencing myelotoxicity requiring dose reduction, the CKD-EPI dose was >25mg higher than actual dose in 20 (59%) patients and >25mg higher than CG dose in 9 (27%) patients.

 

Conclusions

Carboplatin doses calculated using the eviQ-endorsed CKD-EPI formula compared to actual and CG calculated doses were similar in 30%, and were higher than actual dose in 57% of patients. The CKD-EPI dose was higher than actual dose in 59% of patients with clinically significant myelotoxicity. This highlights the ongoing importance of clinician input when dosing carboplatin, taking into account individual patient characteristics.