Marcelo Bonomi, Tamjeed Ahmed, Thomas Lycan, David Warner, Christopher Sullivan, Joshua Waltonen, Kathryn Greven, Bart Frizzell, Mercedes Porosnicu, Katharine Batt, Jimmy Ruiz and Ralph D’Agostino
Background: Concomitant chemo-radiation therapy (CRT) with cisplatin is the mainstay of treatment for patients with locally advanced head and neck cancer. Nephrotoxicity is a well-documented adverse effect of cisplatin, which is exacerbated by dehydration, a common complication in this group of patients. This study prospectively assessed the utility of urine specific gravity (USG) as a guide for fluid replacement, and its preventive effect in cisplatin induced nephrotoxicity.
Methods: Patients with head and neck cancer who received CRT with weekly cisplatin at our institution were included in the analysis. All patients received 1 L normal saline (NS) with 1 g of magnesium and 10 mEq of potassium pre and post cisplatin. USG was measured weekly, patients with USG>1.020 was considered dehydrated and received 2 L NS twice weekly. Those patients with USG>1.025 while on the twice-weekly regimen were deemed very dehydrated and received 2 L NS daily. The primary objective was renal toxicity of any grade.
Results: 44 patients were identified and completed CRT in less than 7.5 weeks. Eighteen of 44 patients (41%) had initial USG>1.020 and were started on NS twice weekly. By week 5, 44 of 44 patients (100%) needed supplemental fluid hydration with only 4 of 44 (9%) requiring daily IV fluids (IVF). No patient experienced renal toxicity of any grade. Five patients (11%) had grade I hypomagnesemia.
Conclusion: USG is a very sensitive marker of dehydration and can be used as a guide for fluid replacement which can minimize cisplatin induced nephrotoxicity in this population.