Treatment Strategies and Metabolic Pathway Regulation in Urothelial Cell Carcinoma: A Comprehensive Review

Cisplatin-based chemotherapy has long been viewed as the first-line chemotherapy for advanced and metastatic urothelial carcinoma (UC). However, many patients with UC have been classified as “cisplatin-ineligible patient”, which requires alternative chemotherapy due to their poor responses. In fact, vast majority of those who initially responded to cisplatin-based chemotherapy eventually progressed. Understanding of UC tumor immunology provided an immunopathogenic bases for immune checkpoint inhibitors, targeting PD-1 and CTLA-4, to treat cisplatin ineligible metastatic UC and patients with platinum-refractory metastatic UC. In 2020, data from the trail further showed that PD-L1 inhibitors benefit prolonged survival and progression-free survival as maintenance therapy. Besides immune-targeting therapies, manipulation of tumor microenvironment via metabolic pathways alternation, such as inhibiting tumor glycolysis, lactate accumulation and exogenous glutamine uptake, has been investigated in the past few years. In this comprehensive review, we started by introducing traditional chemotherapy of UC, and summarized current evidences supporting the use of immune checkpoint inhibitors and highlighted ongoing clinical trials. Lastly, we reviewed the tumor metabolic characteristic and the anti-tumor treatments targeting metabolic pathways.