Neuroendocrine Tumors in Meckel's Diverticulum: Recommendation for Lymphadenectomy Regardless of Tumor Size Based on the NCDB Experience

BackgroundMeckel's diverticulum (MD) is an anomaly of the small intestine from which malignancy may arise. Among MD neoplasms, neuroendocrine tumors (NETs) are considered the most common. However, their metastatic potential and optimal surgical therapy remain ill-defined.MethodsIn a retrospective analysis of the National Cancer Database (2004-2015), patients with a diagnosis of MD malignancy were identified. Clinicopathologic factors were extracted and tumors arising in MD were compared. In the subgroup of patients with NET, the association between tumor factors and node involvement was investigated.ResultsThree hundred twenty primary MD malignancies were captured in the National Cancer Database, consisting of 280 (87.5%) NET. The median age at diagnosis was 64years. Patients were predominantly male (207, 73.9%) and white (269, 96.1%). Most tumors were well-differentiated (118, 42.1%) and sub-centimeter (median size, 0.7cm). Distant metastasis was present in a minority (16, 5.7%), and the median overall survival was 114months in the entire cohort. The regional lymph node status was known in 87 NET patients, out of which 39 (44.8%) harbored node metastasis. Although the risk of node involvement increased with larger tumor size, it remained significant even among sub-centimeter (9 out of 34, 26.5%) and well-differentiated (18 out of 44, 41%) tumors. Regional node involvement was associated with the presence of distant metastasis (p<0.001).ConclusionLymph node involvement was common irrespective of the size and grade of NET arising from Meckel's diverticulum. Therefore, regional lymphadenectomy should be considered in the curative-intent surgical management of these neoplasms regardless of tumor size and grade.