Jad Abou Khalil, Margaret Mandelson, Scott Helton, Adnan Alseidi, Thomas Biehl, Vincent Picozzi, Bruce Lin, Flavio Rocha
Background: Validated benchmarks for adequate lymphadenectomy (LAD) are well established for gastric and colon cancers to avoid stage-migration. Although a harvest of 15 nodes has been proposed for pancreas cancer, this number has not been confirmed in a large, multi-institutional setting. We examined the relationship between LAD and survival in node-negative patients having undergone pancreatectomy for pancreatic adenocarcinoma to identify whether some patients with low lymph node counts are understaged.
Methods: We identified all node-negative patients undergoing pancreaticoduodenectomy (PD) and distal pancreatectomy (DP) for pancreatic adenocarcinoma within the National Cancer Database (NCDB) between 2004 and 2014. We excluded patients with clinical or pathologic M1 disease, as well as patients that died within 90 days from surgery and those with no data on lymph node harvest. Univariate and multivariate quantile regression were used to identify the effect of lymph node harvests and other patient and tumor-specific variables on survival.
Results: We identified 7,329 and 2,071 patients undergoing PD and DP respectively staged as pN0 and meeting inclusion criteria. Median survival was 21.5 (95% CI, 21.1–21.9) and 21.2 (95% CI, 20.1–22.1) months in the PD and DP groups, respectively. In the PD group, LAD ≥15 was not associated with a higher median survival [21.6 (95% CI, 20.9–22.4) and 21.3 (95% CI, 20.7–21.9) months in the <15 and ≥15 LN, respectively, P=0.223]. In the DP group, median survival was 20.2 (95% CI, 19.2–21.6) and 22.6 (95% CI, 20.9–24.4) in the LAD <15 and LAD ≥15 groups (P=0.068). On univariate quantile regression, age, higher tumor grade, lymphovascular invasion, higher T stage, positive margin and not receiving chemotherapy or radiation were associated with decreased survival and retained that association on multivariate regression whereas LAD was not associated with a change in survival in the PD group.
Conclusions: We did not identify a group of patients that were understaged as a function of low lymph nodes harvests. A benchmark of 15 lymph nodes for pancreas cancer cannot be recommended as a quality measure.
