T. Tran1, M. Dua1, G. Poultsides1, J. Norton1, B. Visser1 1Stanford University School Of Medicine,Surgery,Stanford, CA, USA
Introduction: Nodal metastasis is a known prognostic factor for small bowel adenocarcinoma (SBA). Like many gastrointestinal malignancies, inadequate lymph node evaluation may adversely influence survival and lead to understaging. The objective of this study is to evaluate the number of lymph node (LN) that should be retrieved and the impact of lymph node ratio (LNR) on survival.
Methods: The Surveillance, Epidemiology, and End Results database was queried to identify patients diagnosed with SBA and treated with curative surgical resection from 1988 to 2010. Patients who did not undergo lymphadenectomy (Nx) or had distant metastases (M1) were excluded from our analysis. The greatest survival difference for duodenal and jejunoileal tumors was determined using cut-point analysis and maximum log-rank test χ2 statistic. Survival was estimated using Kaplan-Meier method and compared using log-rank test. Multivariate cox proportional hazard model was utilized to identify independent predictors of survival.
Results: A total of 2773 patients underwent surgical resection with lymphadenectomy for SBA from 1988 to 2010. Duodenal and jejunoileal adenocarcinomas each consisted of 50% of all small intestine tumors (n=1387 and n=1386, respectively). There were 1371 patients (49.4%) with negative nodal metastases (N0), whereas 928 (33.5%) and 474 patients (17.1%) had N1 and N2 metastases, respectively. Median LN examined for duodenal and jejunoileal adenocarcinomas were 9 and 8, respectively. Cut-point analysis demonstrated that harvesting at least 9 for jejunoileal and 5 for duodenal tumors resulted in the greatest survival difference. However, there was a significant survival difference for each additional LN examined up to 11 for duodenal and 20 for jejunoileal tumors. Increasing LNR was associated with decreased overall median survival (LNR=0, 71 months; LNR 0-0.2, 35 months; LNR 0.21-0.4, 25 months, and LNR > 0.4, 16 months; p<0.001). This inverse pattern of survival in relation to LNR was observed in the entire cohort (see figure, p<0.001) and each subsite. Multivariate analysis revealed extent of lymph node retrieval, T-stage, and lymph node positivity were independent predictors of survival.
Conclusion: LNR has a profound impact on survival in SBA. In order to achieve adequate staging, we recommend retrieving a minimum of 5 and 9 LN for duodenal and jejunoileal tumors.
