Background: Preoperative/neoadjuvant therapy (NT) is increasingly utilized for the treatment of pancreatic ductal adenocarcinoma (PDAC). However, little data exist regarding information on the use of additional postoperative therapy following NT. The lymph node ratio (LNR) is a prognostic marker of oncologic outcomes after NT and resection. In this study, we evaluated the effectiveness of postoperative therapy following NT, stratified by LNR.
Methods: A prospective tumor registry database was queried to identify patients with PDAC who underwent resection following NT from 1990 to 2008. Clinicopathologic factors were compared to identify associations with overall survival (OS) and time to recurrence (TTR) based on postoperative chemotherapy status.
Results: Thirty-six (14 %) of the 263 patients received additional postoperative therapy. No differences were observed in the pathologic characteristics between patients who received postoperative chemotherapy and those who did not. The median LNR was 0.12 for patients with N + disease. Following NT, the administration of postoperative therapy was associated with improved median OS (72 vs. 33 months; p = 0.008) for patients with an LNR < 0.15. There was no association between postoperative chemotherapy and OS for patients with LNR ≥ 0.15. Multivariate analysis demonstrated that the administration of postoperative systemic therapy in patients with a low LNR was associated with a reduced risk of death (hazard ratio 0.49; p = 0.02).
Conclusion: Postoperative chemotherapy after NT in patients with low LNR is associated with improved oncologic outcomes.