New Trial: SBRT and the Immune System
High dose radiotherapy, such as stereotactic body radiotherapy (SBRT), can deliver highly focused radiation to tumor sites in a non-invasive manner, all while limiting the dose to surrounding organs. Whereas traditional radiotherapy is delivered in lower fractions (~1.8 Gy / treatment) typically over 5-6 weeks, SBRT is delivered at much higher fractions (>8 Gy / treatment) over a much shorter duration (intermittently over the span of 1 to 5 days).
According to Erin Murphy (MD), clinical trial lead and pediatric radiation oncologist at Cleveland Clinic, SBRT is an underutilized tool for young patients with oligometastatic (isolated tumor sites) and unresectable sarcomas. Based on a retrospective analysis of patients treated with SBRT from 2014-2020, this therapy modality has been well tolerated with limited toxicity (no grade 3 acute or late toxicity).1
There are also several key benefits to SBRT for patients, including less of a delay from systemic therapy and a better quality of life.
Lastly, another added benefit is that SBRT has been theorized to be capable of stimulating key immune cells [5]. Early preliminary data from Dr. Murphy’s research suggests that specific immune cell concentrations are modifiable after SBRT, and that these changes in immune cell populations can help accurately predict both local control efficacy and overall survival of these patients. 1, 3.
Building on this theory, a new prospective observational clinical trial (where patients are treated and then followed over time) is now open and available to patients with recurrent or metastatic sarcoma who are eligible to receive SBRT (inclusion/exclusion criteria listed here). In this trial, blood samples will be drawn prior-to and after-SBRT, as well as in a follow-up, to determine the impact of SBRT on the patient's immune system (e.g. measuring and quantifying neutrophil-to-lymphocyte ratio [NTLR], MDSCs, and other immune biological correlates). Results from this trial will help inform the best way to incorporate SBRT into the patient's overall treatment plans and perhaps provide further insight into dovetailing this form of local control with Immunotherapy.
Swords up!
More Information:
Past LWF Blog - SBRT and ImmunoOncology
Ewings U Webinar Recording - SBRT in Pediatric Sarcoma Tumors - Dr. Erin Murphy
Direct Patient Questions about this Trial - Dr. Erin Murphy office number 216-445-4895
Because SBRT is already considered standard care, this trial is not considered a clinical trial and is not on clinicaltrial.gov.
This trial was in-part funded by a $100,000 2021 grant from LWF. Thanks to you, our supporters for helping make this trial become a reality, and thank you to Dr. Murphy for making Sarcoma kids and research a top-priority.