Background: The role of locoregional treatment in oligometastatic oesophago-gastric (OG) cancer remains uncertain, with conflicting trial evidence and limited guidance for clinical practice. This study aimed to evaluate clinician and patient attitudes toward locoregional management, assess clinical equipoise, and explore trade-offs between survival gain and quality of life (QOL) reduction in response to locoregional therapies. Materials and methods: A cross-sectional survey of clinicians involved in multidisciplinary management of OG cancer was conducted between August and December 2025. Scenario-based questions assessed acceptability of combined survival gain (6-15 months) and QOL reduction (5%-20%) as a modified discrete choice experiment. A clustered logistic regression model evaluated the independent effects of survival gain and QOL reduction on clinician acceptability. Patient and public involvement workshops were undertaken to understand patient preferences in potential future trial design. Results: Thirty clinicians from 24 centres participated. Sixty percent reported offering locoregional treatment following stability on systemic therapy. Approximately 93% of respondents indicated willingness to participate in a randomised controlled trial (RCT). Acceptability of treatment strategies increased with greater survival gain and decreased with increasing QOL reduction. In clustered regression analysis, each additional 3 months of survival gain increased the odds of acceptability by ∼75%, whereas each additional 5% QOL reduction decreased the odds by ∼45%. Conclusion: There is substantial variation in clinician attitudes toward locoregional treatment of oligometastatic OG cancer, but marked equipoise and high trial willingness exist. Acceptability is strongly influenced by the balance between survival benefit and QOL impact. These findings support the design of prospective RCTs incorporating patient-centred outcomes.