Patients With Pancreatic Cancer With Synchronous Liver Oligometastasis Show a Significant Long-Term Survival Benefit From Resection Under Specific Conditions: A Multicenter National Cohort Study

Background: In this study, we investigated the criteria that predict the long-term survival benefits after surgical resection in patients with pancreatic cancer accompanied by liver oligometastasis. Methods: In total, 60 patients from 34 high-volume Japanese centers who underwent surgical resection for liver oligometastasis between 2005 and 2020 were included. Univariate and multivariate methods of survival analyses were performed. All patients were followed up for at least 36 months. Results: Overall survival (OS) was significantly longer in the preoperative chemotherapy group than in the up-front surgery group (37.4 vs. 20.4 months, p = 0.001). In the operation with preoperative chemotherapy group, a complete response was observed in eight patients (28.6%). The 1-, 3-, and 5-year OS rates were 92.9%, 50.0%, and 35.7%, respectively. The multivariate analysis showed that low CA19-9 (< 100 U/mL; HR: 0.25; 95% CI: 0.06–0.96; p = 0.043), low CEA (< 5 U/mL; HR: 0.14; 95% CI: 0.04–0.48; p = 0.002), and resectable (R) or borderline resectable pancreatic cancer invading the portal vein (BR-PV) status (HR: 0.19; 95% CI: 0.07–0.51; p < 0.001) were positive prognostic factors. The median OS of the patients who met all three criteria was 106.6 months. Conclusion: Preoperative chemotherapy is essential for the treatment of liver oligometastases. Despite the high recurrence rates, patients who met the specific criteria have a favorable prognosis with liver resection.