Diverting ileostomy is a risk factor for renal impairment during CAPOX therapy

Purpose: Temporary ileostomy is sometimes created after colorectal surgery and may cause renal impairment. However, the impact of ileostomy on renal function during adjuvant chemotherapy for colorectal cancer (CRC) remains unknown. The aim of the present study was to examine the effects of ileostomy on renal function during adjuvant chemotherapy. Methods We examined 184 patients who received adjuvant CAPOX therapy (capecitabine and oxaliplatin) for CRC with or without ileostomy between January 2011 and December 2020 at the University of Tokyo Hospital. Clinicopathological factors, including renal function, were retrospectively reviewed in association with temporary ileostomy. Factors associated with reductions in the estimated glomerular filtration rate (eGFR) during CAPOX therapy were analyzed. Results Eighteen patients (10%) underwent temporary ileostomy. The maximum decrease in eGFR during CAPOX therapy was significantly higher in patients with than in those without ileostomy (-16.1 vs. -5.6 mL/min/1.73m 2 , p  = 0.003). A multivariate analysis identified ileostomy as one of factors independently associated with reductions in eGFR during CAPOX therapy ( p  < 0.001). The cumulative number of readmission was also higher in patients with ileostomy (0.39 vs. 0.05 per person, p  = 0.004). Conclusion Ileostomy significantly reduced eGFR during adjuvant CAPOX therapy. Therefore, renal function needs to be monitored during CAPOX therapy, particularly in patients with ileostomy.