Immunotherapy retreatment: case report, review of the literature and proposal for the definition of different scenarios.

Lay abstract Immunotherapy is an effective treatment option for several types of cancer. It is unclear whether a rechallenge with this treatment could be effective following its discontinuation due to disease progression, treatment toxicity or completion. This is a relevant issue as patients with metastatic cancer have few therapeutic options. Therefore, we share our clinical experience and a literature review about this topic. We report the clinical course of a patient affected by metastatic urothelial cancer whose disease responded to retreatment with immunotherapy after a previous long-term benefit from the same treatment, which was discontinued after 2 years having reached the maximum established treatment duration. We describe the different clinical scenarios of immunotherapy retreatment and factors potentially associated with a benefit from this therapeutic strategy.