Definitive Chemoradiation Associated with Improved Survival Outcomes in Patients with Synchronous Oligometastatic Esophageal Cancer

SIMPLE SUMMARY: Metastatic esophageal cancer is generally treated with palliative intent, prioritizing symptom control over more aggressive treatment. Existing guidelines for metastatic esophageal cancer do not distinguish between many metastases or few: oligometastatic disease. Some research suggests that patients with oligometastatic disease, typically defined as ≤5 sites of metastatic spread, may live longer with more aggressive locoregional therapy. The purpose of this study is to report the clinical outcome of oligometastatic esophageal cancer patients treated with definitive intent chemoradiation to the primary tumor and regional nodal disease at a single institution. ABSTRACT: Background: The study of oligometastatic esophageal cancer (EC) is relatively new. Preliminary data suggests that more aggressive treatment regimens in select patients may improve survival rates in oligometastatic EC. However, the consensus recommends palliative treatment. We hypothesized that oligometastatic esophageal cancer patients treated with a definitive approach (chemoradiotherapy [CRT]) would have improved overall survival (OS) compared to those treated with a purely palliative intent and historical controls. Methods: Patients diagnosed with synchronous oligometastatic (any histology, ≤5 metastatic foci) esophageal cancer treated in a single academic hospital were retrospectively analyzed and divided into definitive and palliative treatment groups. Definitive CRT was defined as radiation therapy to the primary site with ≥40 Gy and ≥2 cycles of chemotherapy. Results: Of 78 Stage IVB (AJCC 8th ed.) patients, 36 met the pre-specified oligometastatic definition. Of these, 19 received definitive CRT, and 17 received palliative treatment. With a median follow-up of 16.5 months (Range: 2.3–95.0 months), median OS for definitive CRT and palliative groups were 90.2 and 8.1 months (p < 0.01), translating into 5-year OS of 50.5% (95%CI: 32.0–79.8%) vs. 7.5% (95%CI: 1.7–48.9%), respectively. Conclusions: Oligometastatic EC patients treated with definitive CRT benefited from that approach with survival rates (50.5%) that vastly exceeded historical standards of 5% at 5 years for metastatic EC. Oligometastatic EC patients treated with definitive CRT had significantly improved OS compared to those treated with palliative-only intent within our cohort. Notably, definitively treated patients were generally younger and with better performance status versus those palliatively treated. Further prospective evaluation of definitive CRT for oligometastatic EC is warranted.