Optimal Lymphadenectomy in Small Bowel Neuroendocrine Tumors: Analysis of the NCDB

Current National Comprehensive Cancer Network guidelines for resectable small bowel neuroendocrine tumors (NETs) recommend regional lymphadenectomy. However, no consensus exists on the optimal nodal harvest.

The National Cancer Database was queried for patients with resectable small bowel NETs (1998-2013). Patients with metastatic disease and missing lymph node harvest data were excluded. We performed logistic regression of factors determining nodal positivity and multivariable survival analyses.

Of 11,852 patients, 81.8% underwent lymphadenectomy. 79.3% were node positive (N+) and 46.9% of patients had tumors < 1 cm. Independent predictors of N+ were large tumor size, ileal location, and neuroendocrine carcinoma histology. Logistic regression found no difference between observed and expected proportions of N+ patients with lymphadenectomy greater than or equal to eight nodes. Lower metastatic node ratio predicted improved survival on multivariable analysis and is associated with high-volume institutions.

Small bowel NETs have high rates of nodal metastasis, even in patients with small tumors, and many patients do not undergo lymphadenectomy despite the clear benefit. Lymphadenectomy of eight nodes is optimal to identify N+ patients. Additionally, minimizing metastatic node ratio with complete regional lymphadenectomy is associated with improved survival in these patients.