Excellent Outcomes With Stereotactic Body Radiotherapy in an Elderly Patient With Locally Progressive Immunotherapy-Resistant Renal Cell Carcinoma.

Clear cell renal cell carcinoma (ccRCC) is typically managed through surgical resection; however, many patients are not eligible for surgery due to advanced age or comorbidities. Stereotactic body radiotherapy (SBRT) has emerged as a promising noninvasive alternative, providing new opportunities for disease control in selected patients. We report the case of an 80-year-old male with metastatic ccRCC, initially treated with nivolumab plus ipilimumab according to the CheckMate 214 protocol. Due to an oligoprogressive renal lesion, SBRT was administered to a total dose of 40 Gy in five fractions (prescription isodose 80%) without significant toxicity. Immunotherapy was discontinued in June 2022 due to immune-related adverse events. Almost five years after SBRT, the treated lesions remain radiologically and clinically stable, despite the long-term discontinuation of systemic therapy. In this case, SBRT proved to be a valuable treatment option for a patient with RCC who was not a candidate for surgery or further systemic therapy. These findings suggest that integrating SBRT into the multimodal management of mRCC may provide prolonged disease control with minimal toxicity in carefully selected cases.