Stereotactic ablative radiation (SAbR) was associated with “meaningful” disease control in patients with oligometastatic renal cell carcinoma (RCC) and also helped patients preserve quality of life, according to a study published in European Urology Oncology.
“There has never been a clinical trial for these patients. It is unclear whether these patients should be treated with medication, surgery, or another approach. This represents an unmet medical need,” said lead author Raquibul Hannan, MD, PhD, Associate Professor of Radiation Oncology, Immunology, and Urology; Chief of the Genitourinary Radiation Oncology Service at UT Southwestern Medical Center.
Based on prior experience Hannan and colleagues hypothesized that SAbR — a treatment that delivers potent, narrow beams of radiation to tumors — may control oligometastatic RCC.
They tested that in this study of 23 patients with systemic therapy-naive oligometastatic RCC. Included patients had three or fewer extracranial metastases. SAbR was administered to 33 initial and 57 total sites. Median follow-up was 21.7 months.
The researchers powered the study to achieve a primary objective of freedom from systemic therapy for more than 1 year in more than 60% of patients. Freedom from systemic therapy at 1 year was achieved in 91.3% of patients.
The 1-year progression-free survival was 82.6%. The local control rate was 100%.
Quality of life was largely unaffected. Most responses to the quality-of-life questionnaires showed no significant change from baseline.
“This study shows that SAbR is safe, is associated with high local control rates, and does not undermine quality of life in patients with oligometastatic RCC, where this intervention was associated with substantial delays in the need for systemic therapy,” the researchers wrote.
A large phase 3 randomized clinical trial evaluating SAbR for oligometastatic kidney cancer has been approved by the National Cancer Institute and will be led by Dr. Hannan.