Pancreatic adenocarcinoma: insights into patterns of recurrence and disease behavior

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers with high metastatic potential. Clinical observations suggest that there is disease heterogeneity among patients with different sites of distant metastases, yielding distinct clinical outcomes. Herein, we investigate the impact of clinical and pathological parameters on recurrence patterns and compare survival outcomes for patients with a first site of recurrence in the liver versus lung from PDAC following original curative surgical resection. Methods: Using the Memorial Sloan Kettering Cancer Center ICD billing codes and tumor registry database over a 10 years period (January 2004-December 2014), we identified PDAC patients who underwent resection and subsequently presented with either liver or lung recurrence. Time from relapse to death (TRD) was calculated from date of recurrence to date of death. Using the Kaplan-Meier method, TRD was estimated and compared by recurrence site using log-rank test Results: The median overall follow-up was 37.3 months among survivors in the entire cohort Median TRD in this cohort was 10.7 months (95%CI: 8.9-14.6 months). Patients with first site of lung recurrence had a more favorable outcome compared to patients who recurred with liver metastasis as the first site of recurrence (median TRD of 15 versus 9 months respectively, P = 0.02). Moderate to poorly or poor differentiation was associated more often with liver than lung recurrence (40% vs 21% respectively, P = 0.047). A trend to increased lymph node metastasis in the lung recurrence cohort was observed. Conclusion: PDAC patients who recur with a first site of lung metastasis have an improved clinical outcome compared to patients with first site of liver recurrence. Our data suggests there may be epidemiologic and pathologic determinants related to patterns of recurrence in PDAC.