Background: The pattern of recurrence affects the clinical outcome in tumor patients. However, the clinical significance of lung metastasis as the primary recurrence site after resection in patients with pancreatic cancer remains unclear. This study aimed to clarify the clinical significance of the primary recurrence site in patients with pancreatic cancer, in terms of prognosis and clinicopathological features.
Methods: This retrospective cohort study included 220 patients with postoperative recurrence after pancreatectomy for pancreatic cancer and classified by primary site of recurrence. We focused on patients with lung metastasis as the primary recurrence and investigated its correlation with prognosis and clinicopathological factors.
Results: Twenty-four (11%) patients had lung metastasis as the primary recurrence. This recurrence pattern had the best prognosis among all recurrence patterns, including liver metastasis and local recurrence. Patients with lung metastasis as the primary recurrence had favorable overall survival and survival from the date of recurrence compared with patients with other primary recurrence sites in both univariate (P = 0.0008 and P = 0.0005) and multivariate analyses (P = 0.0051 and P = 0.0068). In terms of clinicopathological features of resected pancreatic tumors, lung metastasis as the primary recurrence was associated with lower tumor stage and histologic grade, and less vascular invasion and residual tumor volume than liver metastasis.
Conclusions: Pancreatic cancer patients with lung metastasis as the primary recurrence after pancreatectomy have a better prognosis than those with other recurrence patterns.