Pre-hydration in cisplatin-based CCRT: Effects on tumour concentrations and treatment outcome

Pre-hydration is routinely applied to reduce nephrotoxicity in concurrent cisplatin-based chemo-radiotherapy (CCRT). However, pre-hydration may also have systemic effects, potentially leading to lower tumour cisplatin concentrations. We investigated the impact of pre-hydration on tumour cisplatin concentrations in mice, and on treatment outcomes in a clinical cohort study.

Four groups of 20 mice received either no pre-hydration prior to full-dose (6 mg/kg) or half-dose cisplatin, overnight dehydration prior to full-dose cisplatin (dehydration), or NaCl intraperitoneally prior to full-dose cisplatin (pre-hydration). Kidney function and tumour platinum concentration were measured. In patients, a retrospective study compared 2 historical NSCLC cohorts which received CCRT with daily cisplatin, with and without standard pre-hydration. Overall survival (OS) and progression free survival (PFS) were compared using Kaplan-Meier and cox-regression.

Pre-hydration significantly decreased cisplatin tumour concentrations in mice, comparable to mice receiving half the dose. In 419 patients (211 without and 208 with pre-hydration) with median follow-up 22 months, there were no significant differences in PFS (18 vs. 15 months) or OS (23 vs. 23 months).

Pre-hydration reduces cisplatin tumour concentrations in mice, but it does not compromise treatment outcomes in NSCLC patients treated with daily cisplatin and radiotherapy.