Optimal surgery and lymph node metastasis of duodenal bulbar neuroendocrine neoplasms

Abstract Background There is no consensus on the extent of nodal dissection for duodenal bulbar NENs (neuroendocrine neoplasms). Materials and methods We constructed and analyzed a combined dataset consisting of the patients who received surgery in our hospital and the patients from the literature based on a systematic review. The incidence, risk factors and location of nodal metastases were examined. Results Fifty-nine cases including 11 cases managed at our hospital and 48 cases identified from the literature search were examined. Nodal metastasis was observed in 24 patients (40.7%). The 5-year overall survival rate was 100%, regardless of nodal metastasis. Risk factors for lymph node metastasis were tumor size ≥15 mm and muscularis propria or deeper invasion. Stomach-related lymph node metastasis was found in >20% of patients who were positive for at least one risk factor and 15.4% when patients were negative for both risk factors, while pancreas-related lymph node metastasis was observed in 45.5% of patients who were positive for both risk factors, 7.7% who were only positive for one risk factor, and 0% who were negative for both risk factors. Conclusions Tumor size and depth of invasion would determine whether the optimal surgery for duodenal bulbar NENs is distal gastrectomy or pancreatico-duodenectomy.