EA8211 – Phase III Randomized Trial of Stereotactic Ablative Radiotherapy (SAbR) for Oligometastatic Advanced Renal Carcinoma (SOAR)

The study chair for this trial is Raquibul Hannan, MD, PhD and the study co-chair is Suzanne M. Cole, MD (both of the UT Southwestern Medical Center).

The usual treatment for patients with advanced (stage IV) renal cell carcinoma (RCC) that has only spread to a few sites in the body (oligometastatic) is some type of FDA-approved systemic therapy. Many such treatments have been shown to prolong progression-free survival (PFS) and overall survival (OS)—with targeted drugs and immunotherapies among the most common. However, most of these cancers ultimately develop resistance to systemic therapy, mandating changes of systemic agents. Eventually, they run out of effective options. This group of patients may benefit from the use of local therapy to all metastatic sites before systemic treatment. The approach may more effectively control the disease and thus delay the need for systemic therapy, possibly extending patient survival and preserving quality of life (QOL).

One promising local therapy for this patient population is focused stereotactic ablative radiotherapy (SAbR). Prospective phase 2 single-arm trials and retrospective studies of oligometastatic RCC treated with sequential SAbR have reported excellent local control, safety, and median PFS outcomes. Yet no prospective randomized study to date has evaluated the scope of SAbR for longitudinal disease control in patients prior to initiation of first-line therapy. Additionally, no randomized trial has investigated the effect of SAbR on OS, QOL, and the duration of subsequent systemic therapy. 

EA8211/SOAR is the first randomized clinical trial of SAbR versus standard-of-care therapy for patients with oligometastatic RCC whose cancer has spread to two to five sites. Patients who have had surgery to remove the primary RCC will be randomized to receive either standard systemic therapy or sequential SAbR followed by systemic therapy at disease progression. The study’s primary objectives are to compare OS between patients in the two arms and to compare average adverse event scores. Secondary objectives include evaluating quality of life and assessing PFS between the two arms.

The ability of SAbR to potentially control oligometastatic disease and spare patients from the initiation of systemic therapy for months or even years may be profound from a quality-of-life perspective. This approach could help patients avoid frequent clinic visits to monitor drug side effects and prevent or delay the financial burden they often carry while undergoing systemic therapies.

To be eligible for this study, patients must have pathologically proven renal cell carcinoma (RCC) with two to five metastatic lesions (none in the brain). Any RCC histology is acceptable except for those with a sarcomatoid component. Patients may have received prior systemic therapy in the adjuvant setting (following surgery). Otherwise, they must not have received prior systemic treatment for the metastatic RCC.

Learn more about EA8211/SOAR at ecog-acrin.org.