Pulmonary Metastases After Surgical Resection of Pancreatic Ductal Adenocarcinoma: Impact on Long-Term Survival and Perspectives on Targeted Treatments

BACKGROUND: Recurrence impacts outcome after resection for pancreatic ductal adenocarcinoma (PDAC). However, isolated pulmonary metastases exhibit favorable overall survival (OS). Outcomes for patients with pulmonary metastases and concurrent recurrence at other sites are not well studied. This study aimed to assess OS for patients with differing pulmonary recurrence patterns after surgery for PDAC. METHODS: The study included adult patients with PDAC resected between 2009 and 2018 at Karolinska University Hospital. The following three recurrence patterns occurring within 3 years after surgery were compared: metastases involving the liver (liver), pulmonary metastases not involving the liver (lung), and metastases involving neither lung nor the liver (other). Survival analyses with flexible parametric regressions and the Kaplan-Meier method were undertaken. RESULTS: Of 343 patients included in the study, 293 (85%) experienced recurrence within 3 years. The recurrences included 145 (49%) to the liver, 61 (21%) to the lung, and 87 (30%) to other sites. The median OS values for the mentioned groups were 13 months (95% confidence interval [CI], 12-16 months), 30 months (95% CI, 27-35 months), and 20 months (95% CI, 19-26 months) respectively (p ≤ 0.001 for all). Flexible parametric survival regressions showed distinct recurrence-specific mortality risks. Compared with no recurrence, the mortality conferred by the lung was 7-fold higher, by other was 12-fold higher, and by the liver was 23-fold higher (p ≤ 0.001 for all), demonstrating a clear prognostic hierarchy. CONCLUSIONS: Pulmonary metastases, a frequent recurrence pattern after PDAC surgery, exhibit superior OS compared with other sites, even if combined with peritoneal or other distant spread. This finding supports further consideration of targeted treatment strategies for this subgroup.