Main Session
Sep
27
PQA 02 - Pediatric Cancer, Sarcoma and Cutaneous Tumors, Medical Education & Professional Development, and Health Services Research
2314 - Clinical Outcomes of SBRT for Sarcoma Liver Metastases: A Multi-Institution Retrospective Study
Presenter(s)
Zoe Cosner, MD - Harvard Radiation Oncology Program, Boston, MA
Z. L. Cosner1, R. van Dams2, H. J. Roberts3, J. L. Koenig3, E. Choy4, G. Cote4, C. R. Blaszkowsky3, C. Haddox5, S. George5, D. S. Shulman5, T. S. Hong6, H. J. Mamon2, M. Lam2, and J. Y. Wo3; 1Harvard Radiation Oncology Program, Boston, MA, 2Department of Radiation Oncology, Brigham and Women’s Hospital/Dana-Farber Cancer Institute, Boston, MA, 3Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 4Division of Hematology-Oncology, Massachusetts General Hospital, Boston, MA, 5Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA, 6Dana Farber Cancer Institute and Beth Israel Deaconess Medical Center, Boston, MA
Purpose/Objective(s):
Stereotactic Body Radiation Therapy (SBRT) is an established modality for local management of oligometastatic disease across multiple primary histologies, often prolonging systemic therapy-free intervals. However, sarcomas remain underrepresented in prior studies due to their rarity. This study evaluates clinical outcomes of SBRT for sarcoma liver metastases in a retrospective cohort.Materials/Methods:
We identified patients who underwent SBRT for liver metastases with a sarcoma primary histology between 2015 and 2024. Local control (LC), distant progression-free survival (DPFS), overall survival (OS), and time to change in systemic therapy (CST) were analyzed using the Kaplan-Meier method, measured from time of liver SBRT. Local progression was defined as progression at site of treated metastasis, while distant progression included progression outside of the radiation field.Results:
Our cohort consisted of 40 patients treated for 55 liver lesions. The most common histologies were leiomyosarcoma (45%) and Gastrointestinal Stromal Tumor (GIST, 27.5%). Median age at time of liver SBRT was 62 years (range 29-87). Sixteen patients (40%) had undergone prior local therapy to the liver (surgery or cryoablation). Most patients (75%) had metachronous oligometastatic disease, and in 25 patients (62.5%), the liver was the only site of metastatic disease at time of treatment. Additionally, 21 patients (52.5%) had prior radiation to other non-liver sites. The majority (90%) received liver SBRT for oligoprogression, and the remaining patients had stable disease or mixed response to systemic therapy at time of SBRT. Median time from diagnosis of liver metastasis to SBRT was 11 months (range 0.4-159.4). Median dose per fraction was 10 Gy (range 2.5-12) and the most common treatment dose was 10 Gy x 5 (45.5%). Median follow up was 20.6 months (range 0.82 – 74.3). Median OS was 21.5 months (95% CI 16.9-47.8) with 1-year OS of 82.1%. Median DPFS was 5.7 months (95% CI 4.0-8.9). Median LC was 47.8 months (95% CI 45.5-NA) with 1-year LC of 91.1%. Median time to CST was 12.5 months (95% CI 8.8 – 21.3). OS was significantly longer in GIST vs other histologies (54.9 vs 18.9 months, p=0.04) despite similar LC (47.8 vs 53.8 months, p=0.97).Conclusion:
SBRT achieves excellent local control and favorable clinical outcomes for patients with sarcoma liver metastases, comparable to other, non-sarcoma, primary histologies. The median CST of over one year suggests SBRT may successfully delay systemic therapy escalation. These findings help support SBRT as an effective, non-invasive, liver-directed treatment option for patients with oligometastatic sarcoma.