Stereotactic radiation therapy for oligometastatic esophagogastric adenocarcinoma: outcome and prognostic factors.

OBJECTIVES: The aim of this study was to evaluate clinical results and prognostic factors in a cohort of patient with oligometastatic esophagogastric adenocarcinoma treated with Stereotactic Radiation Therapy (SRT).

METHODS: This retrospective study included patients affected by 1 to 3 metastases treated with SRT from 2013 to 2021. Local control (LC), overall survival (OS), progression free survival (PFS), time to polymetastatic dissemination (TTPD) and time to systemic therapy change/initiation (TTS) were evaluated.

RESULTS: Between 2013 and 2021, 55 patients were treated with SRT on 80 oligometastatic sites. Median follow-up was 20 months. Nine patients had local progression. 1 and 3 years LC was respectively 92 and 78%. 41 patients experienced further distant disease progression, median PFS was 9.6 months, 1 and 3 years PFS was respectively 40 and 15%. 34 patients died, median OS was 26.6 months, 1 and 3 years OS was respectively 78 and 40%. During follow up, 24 patients changed or initiated a new systemic therapy; median TTS time was 9 months. Twenty-seven patients experienced poliprogression, 44% after 1 year and 52% after 3 years. Median TTPD was 8 months. The best local response (LR), tyming of metastases and PS were related with prolonged PFS on multivariate analysis. LR was correlated with OS at multivariate analysis.

CONCLUSIONS: SRT represents a valid treatment for oligometastatic esophagogastric adenocarcinoma. CR correlated with PFS and OS, while metachronous metastasis and a good PS correlated with a better PFS.

ADVANCES IN KNOWLEDGE: In selected gastroesopagheal oligometastatic patients, SRT can prolong OSLocal response to SRT, metachronous timing of metastases and better PS improve PFSLocal response correlates with OS.