[Influence of immunomodulators on urological imaging]

Immune checkpoint inhibitors (ICI) have led to great advances in the therapy of metastatic renal cell and urothelial carcinoma. Currently ICI are approved for the first-line therapy of cisplatin-unfit patients (Atezolizumab, Pembrolizumab) and second-line therapy in patients with metastasized urothelial cancer (Atezolizumab, Nivolumab, Pembrolizumab). For the therapy of metastasized RCC, Nivolumab is approved as a second-line therapy and in combination with the CTLA‑4 antibody Ipilimumab as a first-line therapy.

What does the optimized radiological follow-up and therapy response assessment for ICI, which differ in their pathways from common chemotherapeutics and anti-angiogenetic drugs, look like? What strategies are needed to meet the upcoming challenges concerning interpretation of the acquired images?

A systematic literature search was carried out for urothelial and renal cell carcinoma.

Immune-related response criteria have been introduced to better characterize the imaging changes occurring under ICI, as monitoring response to immunotherapy still relies on RECIST.

To properly identify and predict response after treatment with ICI, additional studies with long-term follow-ups are needed. Because of the growing use of ICI, radiologists and urologist should be familiar with common imaging findings (such as pseudo progress) under immunotherapy to correctly interpret these findings in daily routine.