Abstract
BACKGROUND: Oligometastatic disease, characterized by a limited number of metastatic lesions, has gained significant attention for its potential to enable long-term survival with definitive local therapies. Esophageal cancer, an aggressive malignancy often diagnosed at advanced stages, carries a poor prognosis, particularly in cases involving distant metastasis. Stereotactic body radiation therapy (SBRT) has emerged as a promising local treatment modality for oligometastatic disease, offering precise high-dose radiation delivery. This study evaluated the outcomes of SBRT in patients with oligometastatic esophageal cancer. METHODS: This retrospective study analyzed 33 patients with esophageal cancer who underwent SBRT for all oligometastatic lesions at a single institution between August 2014 and March 2024. The inclusion criteria were patients with squamous cell carcinoma, extracranial oligometastases, and no concurrent systemic therapy. Oligometastatic diseases were categorized into de novo, repeat, and induced subtypes. Survival outcomes, including overall survival (OS) and progression-free survival (PFS), were assessed using the Kaplan-Meier method. RESULTS: The study cohort included 33 patients with a median age of 68 years. Most patients had one treated lesion, with SBRT doses ranging from 25-50 Gy in 4-10 fractions. Median OS and PFS were 17.3 months and 4.2 months, respectively. Patients with locoregional recurrence exhibited longer median PFS (5.1 months) and OS (19.6 months) compared to those with distant metastases (PFS: 3.0 months; OS: 14.8 months). Stratification by oligometastatic subtype revealed the best outcomes in de novo cases, with a median OS of 19.6 months and PFS of 8.8 months. Local control at 1 year was 90.7% for the entire cohort, with limited severe late adverse events. CONCLUSION: SBRT demonstrated promising outcomes in patients with oligometastatic esophageal cancer, offering high local control with minimal toxicity. Although these results highlight the feasibility of SBRT, larger prospective studies are needed to validate these findings.