Cisplatin-induced therapy-related myelodysplastic syndrome during avelumab maintenance therapy for metastatic urothelial carcinoma.

A 64 year-old man underwent a radical cystectomy for muscle-invasive bladder cancer. Five years later, lung and mediastinal lymph node metastases were detected. After 15 courses of gemcitabine and cisplatin for metastatic urothelial carcinoma, the patient was switched to avelumab maintenance therapy. During this period, the patient developed a therapy-related myelodysplastic syndrome, leading to difficulty in continuing treatment. Therapy-related myelodysplastic syndrome is a dose-dependent complication that can develop several years after chemotherapy or radiotherapy. Therefore, excessive cisplatin administration should be avoided.