Abstract
Trifluridine/tipiracil (FTD/TPI) has shown efficacy in treating advanced colorectal and gastric cancers. Although renal injury due to FTD/TPI is rare, its renal effects have not been well documented. We present the case of a 74-year-old man with metastatic colon cancer who developed nephrotic syndrome with hematuria after transitioning from a regimen of irinotecan, S-1, and bevacizumab to FTD/TPI. Renal biopsy revealed IgA nephropathy with glomerular microangiopathy (GMA). His condition improved with steroid therapy. To our knowledge, this is the first documented case of nephrotic syndrome associated with FTD/TPI. Renal toxicity should be monitored through urinalysis during FTD/TPI treatment.