The impact of lymph node involvement on adjuvant chemotherapy and survival in patients with resected invasive intraductal papillary mucinous neoplasm: a propensity score matching study based on SEER database and external validation

Background: Limited knowledge and guidelines exist for invasive intraductal papillary mucinous neoplasm (IPMN). This study aims to explore the significance of lymph node involvement on adjuvant chemotherapy (ACT) for invasive IPMN. Materials and methods: Patients diagnosed with invasive IPMN were selected from both the Surveillance, Epidemiology, and End Results (SEER) database and our hospital. Kaplan-Meier analysis, Cox proportional hazards model, and propensity score matching (PSM) were used in this study. Results: In the SEER group, multivariate analysis involving 775 patients revealed that several factors including age, tumor differentiation, the American Joint Committee on Cancer (AJCC) T staging, N staging, and tumor node metastasis classification (TNM) stage significantly influenced overall survival (OS) and cancer-specific survival (CSS). Turning to the Zhongshan Hospital group (ZS group), which had 94 recruited patients, multivariate analysis for OS, CSS, and recurrence-free survival (RFS) showed that AJCC N staging emerged as the most significant risk factor, with hazard ratio (HR) values of 4.664, 4.955, and 3.175, respectively. In subgroup analysis, ACT provided survival advantages for patients with positive lymph node metastasis (LNM). In a PSM analysis focused on patients with positive LNM, the comparison revealed that ACT emerged as a critical factor influencing both OS and CSS (both P < .005). Especially, these patients younger than 60 years old or those with AJCC-T2-N+ staging were found to get apparently benefit from ACT as revealed by our subgroup interaction analysis. Conclusion: LNM plays a pivotal role in the management of invasive IPMN patients who underwent surgery, and ACT might be a beneficial therapeutic option for individuals concurrent with LNM, particularly among those younger than 60 years old, or with AJCC-T2-N+ staging.