Association Between Individualized Estimated Glomerular Filtration Rate and Cumulative Cisplatin Dose in Head and Neck Cancer

<h3>Background/Aim:</h3> In concurrent chemoradiotherapy (CCRT) for head and neck cancer, achieving a cumulative cisplatin dose of ≥200 mg/m² is associated with improved outcomes. However, treatment modification due to toxicity remains a challenge. As cisplatin is primarily excreted by the kidneys, assessment of renal function is important. This study investigated the association between individualized estimated glomerular filtration rate (eGFR) and cumulative cisplatin dose in patients with head and neck cancer undergoing CCRT. <h3>Patients and Methods:</h3> This retrospective study included patients with head and neck cancer who received CCRT with cisplatin (80 mg/m² every three weeks for three cycles) at Niigata University Medical and Dental Hospital between April 2015 and March 2024. The primary endpoint was the cumulative cisplatin dose. Renal function was assessed using individualized eGFR, and patients were categorized into ≥200 mg/m² and &lt;200 mg/m² groups. Logistic regression analysis was performed to identify factors associated with a cumulative cisplatin dose of &lt;200 mg/m². <h3>Results:</h3> Among 158 patients, 27 (17%) received a cumulative cisplatin dose of &lt;200 mg/m². Although all patients had a Cockcroft–Gault creatinine clearance (CGCCr) ≥60 ml/min, 8 (5%) had an individualized eGFR &lt;60 ml/min. The proportion of patients with an eGFR &lt;60 ml/min was significantly higher in the &lt;200 mg/m² group (15% <i>vs</i>. 3%, <i>p</i>=0.03). In the multivariate analysis, eGFR &lt;60 ml/min was associated with a cumulative cisplatin dose &lt;200 mg/m² (adjusted odds ratio=4.66; 95% confidence interval=1.06-20.5; <i>p</i>=0.041). <h3>Conclusion:</h3> In patients with head and neck cancer undergoing cisplatin-based CCRT, individualized eGFR &lt;60 ml/min was associated with a reduced cumulative cisplatin dose despite adequate CGCCr. Assessment using eGFR may improve pre-treatment evaluation of renal function in this setting.