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With the new developments in radiotherapeutic approaches to safely irradiate moving targets, it is now possible to treat kidney lesions with a high enough dose to obtain a good local control.  Because of this, SBRT is now advancing to taking its place next to focal therapies for renal cell carcinoma. The use of SBRT in RCC is currently mostly in the inoperable situation. It was shown by the IRock collective, that also larger lesions can be safely treated. Even in the situation of a vena cava tumor thrombus, for which the resection frequently means a too invasive option and the prognosis is poor, SBRT may be an elegant option in the multimodality treatment setting in combination with immunotherapy.

Cytoreductive nephrectomy used to play a beneficial role in combination with tyrosine kinase inhibitors. In the era of immunotherapy, the role of cytoreductive nephrectomy remains controversial. The Checkmate 214 trial showed that survival rates were better with nivolumab/ipilimumab compared to sunitinib in a group of intermediate/poor-risk patients. It was a mixed population of patients with or without nephrectomy and it was shown, that patients receiving immunotherapy alone can also obtain a good response to the primary tumor. However, overall these patients appear to have a worse outcome when no cytoreductive nephrectomy is performed. Since a nephrectomy is an invasive procedure and radiotherapy could co-stimulate the antitumor immune response, there are now prospective trials available evaluating the use of SBRT as cytoreductive option. These trials treated larger tumors with a moderate dose. The effect SBRT to the kidney function was not significant. In one trial, the kidney was removed directly afterwards. It showed that there was an increase of cytotoxic and regulatory T cells within the tumor. This could be interesting for the combination with immunotherapy. Therefore, the Cytoshrink trial has been proposed, a randomized trial comparing nivolumab/ipilimumab with SBRT to the primary to nivolumab/ipilimumab alone in intermediate/poor risk patients to enhance immunomodulatory effect.

Metastases-directed stereotactic radiotherapy also plays an increasingly important role in RCC patients who are oligoprogressive under immunotherapy and SBRT has been added to the international guidelines as accepted treatment in this situation. This talk will further explore the efficacy and safety of SBRT in (oligo)metastatic patients receiving immunotherapy.