Ki-67 Index and Solid Growth Pattern as Prognostic Markers in Small Intestinal Neuroendocrine Tumors

Prognostic Performance of Different Lymph Node Staging Systems in Patients With Small Bowel Neuroendocrine Tumors

Background: The prognostic significance of the lymph node (LN) classification for small bowel neuroendocrine tumors (SBNETs) remains unknown. The aim of the present study was to evaluate and compare the prognostic assessment of different LN staging systems. Methods: Patients with SBNETs were identified from the Surveillance, Epidemiology, and End Results (SEER) database. The X-tile program was used to determine the cutoff value of the resected lymph nodes (RLNs), negative lymph nodes (NLNs), lymph node ratio (LNR), and the log odds of positive lymph nodes (LODDS). Survival analyses were performed using Kaplan-Meier curves with log-rank test. Logistic regression analysis was used to evaluate the differences between different periods. Univariate and multivariate Cox proportional hazards models were used to assess the prognostic value of different LN staging systems on cause-specific survival (CSS). The relative discriminative abilities of the different LN staging systems were assessed using the Akaike information criterion (AIC) and the Harrell consistency index (HCI). Result: A total of 3,680 patients were diagnosed with SBNETs between 1988 and 2014 from the SEER database. A significant difference over time (1988-1999 vs. 2000-2014) was seen in age (P <0.001), tumor differentiation (P <0.001), T stage (P <0.001), and RLN (P <0.001) subgroups. Multivariate Cox survival analysis identified that LN status stratified by the number of RLNs, NLNs, LNR, and LODDS all predicted CSS in patients with SBNETs (all P <0.05), whereas the number of positive lymph nodes (PLNs) failed (P = 0.452). When assessed using categorical variables, LODDS staging systems showed the best prognostic performance (HCI: 0.766, AIC: 7,575.154) in the whole population. Further analysis based on different RLNs after eliminating the missing data showed that when the RLNs are <12, the LODDS (HCI: 0.769, AIC: 1,088.731) maintained the best prognostic performance as well when the RLNs are ≥12 (HCI: 0.835, AIC: 825.692). Among patients with LNR scores of 0 or 1, there was a residual heterogeneity of outcomes that were better stratified and characterized by the LODDS. Conclusion: LODDS was a better predicator of survival when LN status was stratified as a categorical variable and should be considered when assessing the prognosis of patients with SBNETs to allow a more reliable means to stratify patient survival.

Clinicopathological features and prognostic validity of WHO grading classification of SI-NENs

BACKGROUND

The clinicopathological characteristics of small intestinal neuroendocrine neoplasms (SI-NENs) and the prognostic validity of WHO grading classification for SI-NENs are still unknown in Asian patients.

METHODS

277 patients and 8315 patients with SI-NENs were retrieved respectively from eleven Chinese hospitals and Surveillance, Epidemiology, and End Results (SEER) cancer registry. Overall survival was used as the major study outcome. Survival analysis using Kaplan-Meier analysis with log-rank test and cox regression analysis were applied.

RESULTS

Clinicopathological characteristics of SI-NENs were quite different among different races. Duodenum was the predominant tumor site in Chinese patients and Asian/Pacific Islander patients but not in white patients from SEER database. Patients with duodenal NENs tended to have more localized disease than patients with jejunal/ileal NENs which were confirmed by patients from SEER database. Grade 3 or poorly differentiated/undifferentiated tumor were more common and tumor size was significantly larger in ampullary NENs compared with that in non-ampullary duodenal NENs. As for the prognostic validity of WHO grading classification, survival between patients with grade 1 and grade 2 disease was not significantly different. Ki-67 index of 5% might be a better threshold between grade 1 and grade 2 than Ki-67 index of 2% in SI-NENs.

CONCLUSIONS

Our study revealed that the clinicopathological characteristics of SI-NENs among different races were quite different. This might because duodenal NENs was much more common in Chinese patients and Asian/Pacific Islander patients. Duodenal NENs and jejunal/ileal NENs, ampullary and non-ampullary duodenal NENs shared different characteristics. Ki-67 index of 5% might be a better threshold between grade 1 and grade 2 in SI-NENs.