Distribution of Lymph Node Metastasis and Prognosis in Duodenal Bulb Tumors: A Multicenter Retrospective Study

The optimal surgical procedure for primary duodenal cancer has not been established because of its low incidence. The purpose of this study was to examine the distribution of lymph node (LN) metastasis in duodenal bulb tumors. Specifically, in tumors with submucosal invasion, we aimed to evaluate the feasibility of distal gastrectomy with duodenal bulb resection combined with lymphadenectomy of regional gastric LNs.

Data from patients who underwent surgery for either adenocarcinoma or neuroendocrine tumors located in the duodenal bulb between 2000 and 2020 were retrospectively analyzed from five high-volume centers in Japan. Patient background, clinicopathological factors, type of surgery, distribution of LN metastasis, and long-term outcomes were evaluated.

The frequency of LN metastasis in tumors with submucosal invasion was 18%. Metastatic LNs were identified in T1b adenocarcinomas for #6, #8a, #8p, with similar results for neuroendocrine tumors. The 3-year overall survival rate for adenocarcinoma in stages T1a, T1b, and T2-4 was 100%, 81%, and 56%, respectively. Neuroendocrine tumors were 100% at all depths of invasion. Regarding LN tumors with submucosal invasion, while three patients had a recurrence, two cases were observed in distant organs without regional LNs, and one patient who underwent pancreaticoduodenectomy had metastasis in the gastric regional LNs.

For duodenal bulb tumors, based on the distribution of LN metastasis with tumors with submucosal invasion, distal gastrectomy with duodenal bulb resection and regional LN dissection is considered a curative treatment. Conversely, pancreaticoduodenectomy is recommended for tumors invading the muscularis propria and beyond.