[Immunotherapy in urothelial carcinoma from a pathologist's perspective]

Immunotherapy with programmed cell death protein-1 (PD-1) antibodies (pembrolizumab and nivolumab) has been approved in Europe for the first-line treatment of several tumour entities, e. g. malignant melanoma. Following the resounding therapeutic success of these antibodies in different types of tumours, their potential in urological tumours has been investigated in several studies. The approval of the PD-1 antibody nivolumab for the treatment of metastasised renal cell carcinoma has set a new milestone in urooncology. This success continued with the approval of the programmed cell death ligand 1 (PD-L1) atezolizumab for advanced urothelial carcinoma in 2016. In addition, several ongoing clinical trials of other checkpoint inhibitors have also shown promising efficacy in advanced urothelial carcinoma. The decision to treat a patient with immunotherapy is based, among other things, on the immunohistochemical staining and evaluation by a pathologist. However, due to the lack of standardised evaluation protocols and detection systems, it is difficult to compare different studies and evaluate the efficacy of the respective antibodies.