(UroToday.com) In the eleventh session of the 2022 International Kidney Cancer Symposium (IKCS): Europe meeting focusing on the role of radiation therapy in the management of kidney cancer, Dr. Kroeze presented on the role of radiotherapy in the management of patients with renal cell carcinoma (RCC).
She began that emphasizing that recent technological evolutions in radiotherapy technique, particularly with the ability to focus therapy on moving targets with the use of sterotactic body radiotherapy, have been critical in facilitating safe treatment of RCC with ablative doses of radiotherapy. This approach, so far, has typically been employed in the context of inoperable tumors or patients. Some the first data in this regard came from a single arm prospective trial performed by Dr. Sia. Among 33 inoperable patients with RCC, he and his group demonstrated that SBRT was safe and feasibly with 3% rates of grade 3 toxicity and 100% two-year local control rates. However, they did not that there was an exponential decline in renal function for every 10 Gy delivered. In a larger multicenter retrospective study (IROCK) of patients with larger tumors (pT1b or greater), his group again showed that SBRT was a feasible approach for the treatment of these larger tumors. Overall, it was well tolerated and the impact of renal function was modest though 3% of patients did require a new dialysis start.
Among a smaller sample of 15 patients with inoperative RCC with vena caval thrombus, Freifeld and colleagues showed that SBRT was feasible with no severe toxicity and favourable overall survival compared to historical untreated controls. This suggests a potential for multimodal therapy in this setting.
Dr. Kroeze emphasized that this approach is most appropriate for patients who are older and frail. In this subset of patients, a recent retrospective analysis of 23 patients with a median age of 81 years and Charlson comorbidity score of 7 showed SBRT to be feasible and well tolerated with promising cancer control (96% two-year local control rate). Further, there was a relatively modest effect on renal function.
Thus, she emphasized that these “pioneering studies” show that treatment may give good local control with minimal or manageable toxicity.
Moving from the local and locally advanced disease space into metastatic disease, she emphasized that the role of cytoreductive nephrectomy is changing. However, data from CheckMate 214 suggest better survival for patients receiving nivolumab and ipilimumab who have undergone prior nephrectomy. An alternative to nephrectomy may be for cytoreductive SBRT in this setting. She highlighted two studies showing that SBRT was feasible for patients with large, inoperable tumors in the setting of metastatic disease. However, these studies didn’t include systemic targeted therapy or immunotherapy therapy which would be the standard of care for most patients with metastatic disease. To address this, the CYTOSHRINK trial is a phase II randomized controlled trial of nivolumab and ipilimumab with or without SBRT in patients with intermediate and poor risk RCC. The rationale of SBRT here is to enhance the efficacy of the systemic immunotherapy, potentially through upregulation of immune modulation.
Presented by: Stephanie Kroeze, MD, PhD, Radiation Oncologist, at Universitätsspital Zürich
Written by: Christopher J.D. Wallis, University of Toronto, Twitter: @WallisCJD during the 2022 International Kidney Cancer Symposium (IKCS) Europe Annual Hybrid Meeting, Antwerp, Belgium, Fri, Apr 22 – Sun, Apr 24, 2022.