Role of Removed Lymph Nodes on the Prognosis of M0 Small-Bowel Neuroendocrine Tumors: a Propensity Score Matching Analysis from SEER Database

Abstract

Background Current studies on the number of removed lymph nodes (LNs) and their prognostic value in small-bowel neuroendocrine tumors (SBNETs) are limited. This study aimed to clarify the prognostic value of removed LNs for SBNETs. Methods SBNET patients without distant metastasis from 2004 to 2017 in the SEER database were included. The optimal cutoff values of examined LNs (ELNs) and negative LNs (NLNs) were calculated by the X-tile software. Propensity score matching (PSM) was done to match patients 1:1 on clinicopathological characteristics between the two groups. The Kaplan-Meier method with log-rank test and multivariable Cox proportional-hazards regression model were used to evaluate the prognostic effect of removed LNs. Results The cutoff values of 14 for ELNs and 9 for NLNs could well distinguish patients with different prognoses. After 1:1 PSM, the differences in clinicopathological characteristics between the two groups were significantly reduced (all P > 0.05). Removal of more than one LN significantly improved the prognosis of the patients (P < 0.001). The number of lymphatic metastasis in the sufficiently radical resection group (SRR, 3.74 ± 3.278, ELN > 14 and NLN > 9) was significantly more than that in the insufficiently radical resection group (ISRR, 2.72 ± 3.19, ELN < 14 or NLN < 9). The 10-year overall survival (OS) of the SRR was significantly better than that of the ISRR (HR = 1.65, P = 0.001, 95% CI: 1.24–2.19). Conclusion Both ELNs and NLNs can well predict the OS of patients. Systematic removal of more than 14 LNs and more than 9 NLNs can increase the OS of SBNET patients.

Survival comparison between endoscopic and surgical resection for non-ampullary duodenal neuroendocrine tumor (1–2 cm)

“…After matching, our results showed that the surgical approach, tumor size, sex, race, income, TNM stage, and tissue type were not correlated with either DSS or OS, but the tumor grade was correlated with prognosis ( P < 0.006), in line with the findings reported by Margonis et al 14 , and patients aged less than 60 years had better 5-year OS than those aged older than 60 years ( P = 0.001). In view of surgical resection is too aggressive and accompanied by serious surgical risks for the local disease, endoscopic treatment, as the main treatment method for tumors ≤ 1 cm, has the significant advantages of a short operation time, low cost, short hospital stay, and low impact on quality of life 7 , 8 .…”

“…P < 0.05 was considered statistically significant (two-tailed tests). The MatchIt package of R software v3.6.3 ( https://www.R-project.org ) was used to perform 1:1 PSM with a caliper value set to 0.1 for sex, race, income, tumor size, T stage, N stage, M stage, TNM stage and histologic type 14 . The nearest-neighbor matching method was used to match the baseline characteristics between the two groups.…”

Development and validation of a clinical cure marker based on negative lymph nodes for gastric cancer after gastrectomy

“…To ensure the accuracy and generality of the results, patients were randomly divided into training and validation cohorts, and then clinical cure and nonclinical cure groups were matched by PSM for baseline imbalance. This method can simulate randomized controlled trials well and improve the reliability of the results ( 20 ). There were significant differences between the clinically cured and noncured groups in age, sex, race, tumor location, surgical methods, and histologic type.…”

Critical updates in neuroendocrine tumors: Version 9 American Joint Committee on Cancer staging system for gastroenteropancreatic neuroendocrine tumors

“…40 Additional studies have demonstrated that the number of lymph nodes removed has prognostic significance, with better survival in patients who underwent a more extensive lymphadenectomy. [41][42][43] The lack of hierarchical prognostication by stage group observed in the AJCC survival analysis may be caused by insufficient lymph node dissection, leading to inaccurate staging.…”

“…A retrospective study on 691 patients with jejunal‐ileocecal NETs found no significant difference in survival between stage I/II and III midgut NETs, with further analysis showing that, among patients who had stage III NETs, 5‐year survival for those with resectable tumors who also underwent a lymph node dissection was significantly better than for those whose tumors were unresectable 40 . Additional studies have demonstrated that the number of lymph nodes removed has prognostic significance, with better survival in patients who underwent a more extensive lymphadenectomy 41–43 . The lack of hierarchical prognostication by stage group observed in the AJCC survival analysis may be caused by insufficient lymph node dissection, leading to inaccurate staging.…”