GU Symposium 2021: Radiotherapy Plus Pembrolizumab for Oligometastatic Kidney Cancer
Posted: Monday, March 8, 2021
Stereotactic ablative body radiotherapy (SABR) in addition to pembrolizumab seemed to be well tolerated in patients with oligometastatic clear cell renal cell carcinoma, according to Shankar Siva, PhD, of the Peter MacCallum Cancer Centere, Melbourne, and colleagues. The results of the multicenter phase I/II RAPPORT trial, which were presented during the virtual edition of the 2021 Genitourinary (GU) Cancers Symposium (Abstract 277), suggested this combination also demonstrated “excellent” local tumor control.
“These findings suggest that radiation therapy may prime the tumor via an Abscopal effect and render a better response to immunotherapy,” commented Robert G. Uzzo, MD, MBA, FACS, of Fox Chase Cancer Center, Philadelphia, in an American Society of Clinical Oncology press release. “Studies like these are essential in an effort to improve, augment, and sequence current therapies into more meaningful and measurable treatment algorithms for advanced kidney cancers.”
A total of 30 patients with between one and five oligometastases were enrolled and received protocol treatment. They were administered a single fraction of 20 Gy of SABR to all metastatic sites before pembrolizumab; however, if SABR was not feasible, 10 fractions of 3 Gy of conventional radiotherapy were administered. Of the 83 treated oligometastases, 77% received SABR, and 23% received conventional radiotherapy.
Grade 3 treatment-related adverse events occurred in 13% of patients; no adverse events of grades 4 or 5 were reported. The majority of patients (80%) completed all eight cycles of pembrolizumab. The disease control and objective response rates were 83% and 63%, respectively. The median duration of progression-free survival was 15.6 months. The estimated overall survival rate was 90% at 1 year and 74% at 2 years; the estimated progression-free survival rates were 60% and 45%, respectively. At 2 years, the rate of freedom from local tumor progression was 92%.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.