1245P - A lymph nodal staging assessment model for various histologic types of small intestinal tumors

Background

Specific requirements of the minimum number of harvested lymph nodes for accurate nodal staging in small intestinal tumors are sparse as there is a probability that false-negative lymph nodes remain. The aim of this study is to establish a histologic-type-specific nodal staging score (NSS) model for the specific requirements of lymph nodes in small intestinal tumors by taking potential false-negative lymph nodes into consideration.

Methods

Small intestinal tumors with complete follow-up and examined/positive lymph nodes data were retrieved using the Surveillance, Epidemiology, and End Results program. Using a beta-binomial model, the probability of lymph nodes with occult disease and the NSS model were established.

Results

A total of 7649 small intestinal tumors were retrieved, including 3789 carcinoid cases, 2467 adenocarcinoma cases, 718 neuroendocrine carcinoma cases, 502 sarcoma cases, and 173 others. To reach a 0.05 false-negative probability, the minimum number of lymph nodes was 10 in carcinoid tumors, 11 in adenocarcinoma, 12 in neuroendocrine carcinoma, 7 in sarcoma, and 16 in others. Distinct NSS curves were presented among each histologic type of small intestinal tumors. The NSS of neuroendocrine carcinoma indicated that a higher number of lymph nodes was required to enable the correct staging of lymph nodes compared to other types of small intestinal tumors. The prognostic values of NSS quartiles were validated.

Conclusions

The minimum required number of examined lymph nodes varied in each histologic type of small intestinal tumors. The NSS improved the adequacy of nodal staging for patients for clinical interpretation and decision making.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.