The Diagnosis and Treatment Approach for Oligo-Recurrent and Oligo-Progressive Renal Cell Carcinoma

Simple Summary Oligo-recurrence and oligo-progression in oncology refer to scenarios in which five or fewer metastases develop after the primary lesions and other metastases have been treated using radical surgery or controlled using systemic therapy. Such scenarios are now considered favorable indications for metastasis-directed treatment (MDT), where a curative approach is possible. The primary strategy for recurrence and metastases in renal cell carcinoma (RCC) is systemic therapy, which includes immune checkpoint inhibitors (ICIs) and vascular endothelial growth factor receptor tyrosine kinase inhibitors. However, MDTs such as stereotactic body radiation therapy, which involves larger doses administered over fewer fractions than conventional radiation therapy, have shown the potential to improve outcomes for selected patients with RCC experiencing oligo-recurrence and oligo-progression. Combining MDT with ICIs may yield better results owing to their synergistic effects. In this review, we provide an overview of the current evidence related to the management of oligo-recurrent and -progressive RCC.Abstract One-third of renal cell carcinomas (RCCs) without metastases develop metastatic disease after extirpative surgery for the primary tumors. The majority of metastatic RCC cases, along with treated primary lesions, involve limited lesions termed "oligo-recurrent" disease. The role of metastasis-directed therapy (MDT), including stereotactic body radiation therapy (SBRT) and metastasectomy, in the treatment of oligo-recurrent RCC has evolved. Although the surgical resection of all lesions alone can have a curative intent, SBRT is a valuable treatment option, especially for patients concurrently receiving systemic therapy. Contemporary immune checkpoint inhibitor (ICI) combination therapies remain central to the management of metastatic RCC. However, one objective of MDT is to delay the initiation of systemic therapies, thereby sparing patients from potentially unnecessary burdens. Undertaking MDT for cases showing progression under systemic therapies, known as "oligo-progression", can be complex in considering the treatment approach. Its efficacy may be diminished compared to patients with stable disease. SBRT combined with ICI can be a promising treatment for these cases because radiation therapy has been shown to affect the tumor microenvironment and areas beyond the irradiated sites. This may enhance the efficacy of ICIs, although their efficacy has only been demonstrated in clinical trials.