Adjuvant Chemotherapy Is Not Associated With Improved Overall Survival in Patients With Pancreatic Ductal Adenocarcinoma With Persistent Lymphovascular Invasion or Lymph Node Involvement After Neoadjuvant Chemotherapy.

BACKGROUND AND OBJECTIVES: There is increasing use of neoadjuvant treatment (NAT) for patients with pancreatic adenocarcinoma (PDAC). The role of additional adjuvant chemotherapy (AT) is not well-defined. This study aims to determine the impact of lymphovascular invasion (LVI) and lymph node (LN) involvement on overall survival (OS) in patients with resected PDAC and determine the impact of AT after NAT. METHODS: This is an observational cohort study of patients with PDAC who underwent NAT and surgical resection. A multivariable model was used to assess for differences in OS. An interaction term between LVI or LN involvement and AT use was utilized to test the benefit of additional AT. RESULTS: Seven thousand four hundred and fourteen patients were included; group A (LVI-, LN-) had 2787 patients, B (LVI + , LN-) 652, C (LVI-, LN + ) 1,712, and D (LVI + , LN + ) 2263. Median OS differed significantly between groups, A had the most favorable survival (34.1 months), followed by B (27.8 months), C (26.3 months), and D (21.2 months, p < 0.001). In patients with persistent LVI or LN involvement after NAT, additional AT was not associated with OS (group A, HR: 0.94, p = 0.4; B and C, HR: 1.0, p = 0.99; D, HR: 0.94, p = 0.32). CONCLUSIONS: LVI and LN involvement were independently associated with worse OS. After NAT, the use of AT in patients with persistent LVI and LN involvement was not associated with improved OS.