Background: No standard chemotherapy regimen for advanced urothelial cancer has been established, except for cisplatin-based regimens. We report the case of a patient with double primary cancer, urothelial carcinoma of the upper urinary tract and colorectal cancer, who underwent oxaliplatin-based chemotherapies. Case presentation: A 56-year-old Japanese man presented to our hospital with the diagnosis of a left renal pelvic tumor and rectal cancer. Several examinations including ureteroscopic biopsy and computed tomography-guided biopsy were performed; however, the diagnosis of renal pelvic cancer could not be made. Because the rectal cancer had been growing during the course of examination, he underwent five cycles of neoadjuvant chemotherapy with fluorouracil, leucovorin, oxaliplatin, and irinotecan. The volumes of both the rectal cancer and renal pelvic tumor drastically decreased. He then underwent pelvic evisceration with colostomy and ureterocutaneostomy. The histological diagnosis of the renal pelvic tumor was urothelial carcinoma. He is free of disease at 12 months after the treatment. Conclusions: To the best of our knowledge, this is the first report describing a remarkable response to fluorouracil, leucovorin, oxaliplatin, and irinotecan therapy for renal pelvic cancer. We suggest fluorouracil, leucovorin, oxaliplatin, and irinotecan is an effective therapy for patients with advanced urothelial cancer.
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