Stereotactic Body Radiotherapy for Renal Cell Carcinoma—A Review of Use in the Primary, Cytoreductive and Oligometastatic Settings.

Simple Summary: Stereotactic body radiotherapy (SBRT) is a treatment technique that delivers higher doses of conformal radiation precisely to specific targets. SBRT is utilized for the treatment of the more common cancers such as lung, liver and prostate malignancies, both in the early stage and the oligometastatic setting. The aim of this review is to highlight the current role of SBRT for renal cell carcinoma (RCC), a disease which was previously thought to be radioresistant, particularly to conventionally fractionated radiotherapy. There is now an increasing body of literature encompassing published phase II trials, reviews and meta-analyses demonstrating the effectiveness of SBRT in both early-stage RCC (as an alternative to patients who are not surgical candidates) and within the context of metastasis-directed therapy (MDT) for patients with oligometastatic and oligoprogressive RCC. Ongoing randomized trials are also exploring the role of SBRT as a cytoreductive treatment in metastatic RCC. Renal cell carcinoma (RCC) has been increasing in incidence by around 1.5% per year for several years. However, the mortality rate has been decreasing by 1.6% per year, and this can be attributed to stage migration and improvements in treatment. One treatment modality that has emerged in recent years is stereotactic body radiotherapy (SBRT), which is an advanced radiotherapy technique that allows the delivery of high-dose radiation to the tumor while minimizing doses to the organs at risk. SBRT has developed a role in the treatment of early-stage, oligometastatic and oligoprogressive RCC. In localized disease, phase II trials and meta-analyses have shown that SBRT provides a very high probability of long-term local control with a low risk of severe late toxicity. In oligometastatic (OMD) RCC, the same level of evidence has similarly shown good local control and minimal toxicity. SBRT could also delay the necessity to start or switch systemic treatments. Medical societies have started to incorporate SBRT in their guidelines in the treatment of localized disease and OMD. A possible future role of SBRT involves cytoreduction. It is theorized that SBRT can lower tumor burden and enhance immune-related response, but it cannot be recommended until the results of the phase II trials are published. [ABSTRACT FROM AUTHOR]