PD04.06. Identifying Oligometastatic Recurrence in Esophageal Squamous Cell Carcinoma After Radical Esophagectomy Through Longitudinal Analysis

Abstract

Esophageal Cancer: Management of Metastatic Cancer The definition of oligometastatic recurrence in esophageal squamous cell carcinoma (ESCC) remains a subject of debate. We investigated the clinical criteria for oligometastatic recurrence in ESCC by analyzing the tumor kinetics and longitudinal patterns of recurrence in patients after curative esophagectomy. Eighty-seven patients with recurrent ESCC between 2011 and 2018 were retrospectively reviewed. The cumulative number of lesions and the sum of maximum short-axis diameters (SSD) were tracked longitudinally. We evaluated the association between tumor kinetics, recurrence sites, and post-recurrence survival (PRS) to propose the oligometastatic recurrence criteria. At 12 months post-recurrence, more than 80% of evaluable patients maintained three or fewer cumulative lesions, and approximately 70% had an SSD of 30 mm or less. Specific recurrence patterns, including liver metastasis, para-aortic lymph node involvement, and dissemination, showed distinctively aggressive kinetics. Based on these findings, we defined oligometastatic recurrence in ESCC as maintaining ≤ 3 lesions and an SSD ≤ 30 mm at a 6-month observation point (excluding the high-risk sites mentioned above). The 3-year PRS was significantly superior in the oligometastatic recurrence group compared to the non-oligometastatic recurrence group (p < 0.001). Multivariate analysis for 3-year PRS identified our criteria for oligometastatic recurrence as a potent independent associated factor. Incorporating a 6-month observation period allows for the identification of a favorable population with oligometastatic recurrence in ESCC. These criteria may serve as a critical framework for selecting candidates for local consolidation therapy.