SBRT for Oligoprogressive Non-Small Cell Lung Cancer: A Single Institutional Retrospective Review examining differences in continued versus altered systemic therapy

Summary: Stereotactic body radiotherapy (SBRT) has been demonstrated as an effective treatment for oligoprogressive cancer in improving progression-free survival (PFS) and local control, specifically in non-small cell lung cancer (NSCLC)1. We performed a retrospective review of patients who underwent SBRT for extra-cranial oligoprogressive NSCLC at our institution with a primary endpoint of PFS, while examining potential differences in PFS for patients remaining on same line of systemic therapy versus those who had changes in their systemic therapy. After IRB approval, we retrospectively reviewed patients identified by using an in-house C# LINQ query with a Treatment Summary containing the text “NSCLC” and then filtered for any instance of extra-cranial oligoprogression treated with SBRT. Oligoprogression was defined as ≤ 5 sites of progression after receiving first-line treatment. Of the included patients, we reviewed clinicopathological documentation to determine demographics, tumor biology, initial treatment regimens, radiation and systemic treatment and determine the time to progression, death, or last follow-up. Analysis was performed using Kaplan-Meier Method. A total of 23 patients were identified that received SBRT for extra-cranial oligoprogressive NSCLC from 2018 to 2023 with a median follow-up of 12.5 months. 29 total courses of SBRT were delivered, with four patients receiving two courses and one patient receiving three courses of SBRT for subsequent oligoprogression. Sites treated included lung, liver, adrenal glands, axillary nodes, and bone. Radiation doses ranged from 16 - 55 Gy treated in 1 - 5 fractions, depending on the site. The median PFS after all courses of SBRT was 12.5 months (IQR 4.9 – 22.9 months). Of the 29 treatments, 19 courses were associated with continuation of the same systemic treatment, while 10 courses were associated with a change in systemic therapy management. Of the courses with continuation of the same line of systemic treatment, the median PFS was 14.2 months (IQR 5.1 – 24.2 months) vs 12.6 months for those associated with a change (IQR 4.5 – 20.5 months) (p = 0.4316). No grade 3 or higher radiation toxicities were reported. This institutional retrospective review agrees with previously reported data demonstrating SBRT as an effective treatment modality for oligoprogressive NSCLC with a relatively safe toxicity profile, providing a durable PFS benefit regardless if current systemic therapy is continued or altered. Our next steps include focusing on tumor biology and how it may help identify which patients would most likely benefit from continuing their same systemic therapy following SBRT. Our hope is that this review will provide valuable insights into the evolving landscape of SBRT and personalized treatment for NSCLC. John Knoth, MD (Presenting Author) - Department of Radiation Oncology, West Virginia University Cancer Institute; Matthew Trotta, MD (Co-Author) - Department of Radiation Oncology, West Virginia University Cancer Institute; Adrienne Duckworth, AOCNP (Co-Author) - West Virginia University, Department of Medical Oncology; Joseph Schmidlen, BS (Co-Author) - West Virginia University, School of Medicine; Naveen Joseph, BS (Co-Author) - West Virginia University, School of Medicine; Cody R. Kilar, DO, PhD (Co-Author) - Department of Radiation Oncology, West Virginia University Cancer Institute; Casey Mozingo, FNP-C (Co-Author) - West Virginia University, Department of Radiation Oncology; Maher Alabboodi, PhD (Co-Author) - West Virginia University, Department of Radiation Oncology; Ramon A. Siochi, PhD, DABR (Co-Author) - Department of Radiation Oncology, West Virginia University Cancer Institute; David Clump, MD, PhD (Co-Author) - West Virginia University, Department of Radiation Oncology; Mohammed Almubarak, MD (Co-Author) - West Virginia University, Department of Medical Oncology; Phillip Pifer, MD, PhD (Co-Author) - West Virginia University, Department of Radiation Oncology