Local Treatment for Oligometastatic Recurrence After Curative Resection for Pancreatic Ductal Adenocarcinoma: An Integrated Analysis of Liver and Lung Recurrence

Background/Objectives: Although local treatment has been increasingly applied to oligometastatic pancreatic ductal adenocarcinoma (PDAC), it remains unclear whether radiologically defined oligometastatic disease identifies patients who benefit from local treatment. We evaluated the survival impact of local treatment according to recurrence burden after curative resection of PDAC. Methods: We retrospectively reviewed patients who developed isolated liver or lung recurrence after curative-intent resection for PDAC between 2012 and 2021. Overall survival (OS) was compared according to metastatic organ, metastatic burden, and treatment strategy. Results: Among 269 patients (194 with liver and 75 with lung recurrences), those with lung recurrence, including those with oligometastatic disease, had significantly longer OS than those with liver recurrence. Although oligometastatic recurrence was associated with more favorable survival than multiple recurrences, no significant association between local treatment and longer OS was observed in either the liver or lung oligometastatic group in the conventional analysis. In patients with solitary lung recurrence, local treatment was associated with longer OS in the conventional analysis, but this association did not reach statistical significance in the time-dependent Cox analysis. Conclusions: Radiologically defined oligometastatic recurrence was associated with a favorable prognosis but was insufficient to identify patients likely to benefit from local treatment. Although an association between local treatment and longer survival was observed in patients with solitary lung recurrence, this finding was not statistically significant in the time-dependent Cox analysis and requires further validation.