Duodenal neuroendocrine tumors: Somewhere between the pancreas and small bowel?

While sub-2 cm pancreatic neuroendocrine tumors (NETs) are often observed, small bowel-NETs undergo resection and lymphadenectomy regardless of size. Aim was to define the natural history of duodenal (D-NETs), determine the role of resection, and define the factors associated with overall survival (OS) after resection.

National Cancer Database (2004-2014) was queried for the patients with nonmetastatic/nonfunctional D-NETs. Local resection (LR): local excision/polypectomy/excisional biopsy. Anatomic resection (AR): radical surgery. Tumor size was divided into less than 1 cm, 1 to 2 cm, and ≥2 cm. Propensity score weighting was used to create balanced resection and no-resection cohorts. The primary endpoint was OS.

Among 5502 patient, the median age was 65 years. The median follow-up was 49 months. The median tumor size was 0.8 cm. Resection was performed in 72% (n = 3954; LR: 61%, AR: 39%). Lymph node (LN) resection was performed in 26% (43% had metastasis). A total of 74% had negative margins. Resection and no-resection cohorts were propensity score weighted for age/sex/race/Charlson-Deyo score/tumor grade (all independently associated with OS on multivariable analysis). Resection was associated with improved median OS compared to no resection in all sizes (<1 cm: median not reached vs 194 months; 1-2 cm: median not reached vs 56 months; >2 cm: median not reached vs 90 months; all P < .01). Subset analysis of each resection size cohort demonstrated that neither type of resection, LN retrieval, LN positivity, or margin status was associated with OS (all P > .05).

Patients with nonmetastatic and nonfunctional D-NETS should be considered for resection regardless of tumor size. Given the lack of prognostic value, the resection type and extent of LN retrieval should be tailored to each patient's clinical picture and safety profile.