Prognostic significance of lymph node metastases in small intestinal neuroendocrine tumors

[Local resection of small intestine neuroendocrine neoplasms (SI-NEN) : Current principles]

BACKGROUND

Neuroendocrine tumors of the small bowel (small intestine neuroendocrine neoplasms, SI-NEN) are the most frequent tumors of the small intestine and approximately 30-40% are still surgically treatable with curative intent at the time of diagnosis. Certain surgical principles must be followed for optimal oncological outcomes and good postoperative quality of life.

METHODS

Based on international guidelines and own experiences, the locoregional surgical treatment of SI-NENs is presented.

RESULTS

Locoregional SI-NENs should always be resected if technically feasible, as only this approach can achieve a long-term cure and even small primary tumors (< 10 mm) often already show lymphatic metastasis. The resectability of SI-NENs and their difficulty depend on the extent of lymphatic metastasis, which should be assessed based on preoperative imaging of the extent around the superior mesenteric artery. Currently, the surgical gold standard for SI-NENs is open surgery with bidigital palpation of the entire small intestine followed by primary tumor resection via small bowel segment resection, right hemicolectomy or ileocecal resection and vessel-sparing, and therefore organ-preserving lymphadenectomy (≥ 8 lymph nodes). The guidelines consider that laparoscopic or robotic approaches are justified only for early stages of SI-NENs.

CONCLUSION

Guideline-compliant surgical treatment of locoregional SI-NEN enables recurrence-free long-term survival with good quality of life.

The Need for Centralization for Small Intestinal Neuroendocrine Tumor Surgery: A Cohort Study from the GTE-Endocan-RENATEN Network, the CentralChirSINET Study

BACKGROUND

The concept of surgical centralization is becoming more and more accepted for specific surgical procedures.

OBJECTIVE

The aim of this study was to evaluate the relationship between procedure volume and the outcomes of surgical small intestine (SI) neuroendocrine tumor (NET) resections.

METHODS

We conducted a retrospective national study that included patients who underwent SI-NET resection between 2019 and 2021. A high-volume center (hvC) was defined as a center that performed more than five SI-NET resections per year. The quality of the surgical resections was evaluated between hvCs and low-volume centers (lvCs) by comparing the number of resected lymph nodes (LNs) as the primary endpoint.

RESULTS

A total of 157 patients underwent surgery in 33 centers: 90 patients in four hvCs and 67 patients in 29 lvCs. Laparotomy was more often performed in hvCs (85.6% vs. 59.7%; p < 0.001), as was right hemicolectomy (64.4% vs. 38.8%; p < 0.001), whereas limited ileocolic resection was performed in 18% of patients in lvCs versus none in hvCs. A bi-digital palpation of the entire SI length (95.6% vs. 34.3%, p < 0.001), a cholecystectomy (93.3% vs. 14.9%; p < 0.001), and a mesenteric mass resection (70% vs. 35.8%; p < 0.001) were more often performed in hvCs. The proportion of patients with ≥8 LNs resected was significantly higher (96.3% vs. 65.1%; p < 0.001) in hvCs compared with lvCs, as was the proportion of patients with ≥12 LNs resected (87.8% vs. 52.4%). Furthermore, the number of patients with multiple SI-NETs was higher in the hvC group compared with the lvC group (43.3% vs. 25.4%), as were the number of tumors in those patients (median of 7 vs. 2; p < 0.001).

CONCLUSIONS

Optimal SI-NET resection was significantly more often performed in hvCs. Centralization of surgical care of SI-NETs is recommended.

Surgical and Endoscopic Resection of Duodenal Neuroendocrine Tumors Have Similar Disease-Specific Survival Outcome

BACKGROUND

Duodenal neuroendocrine tumors (dNETs) are rare, and their management is not well-defined. National Comprehensive Cancer Network (NCCN) guidelines recommend surgical resection of large dNETs (> 2 cm) and endoscopic resection of small tumors (< 2 cm). We compared the survival outcomes between surgical and endoscopic resection in various dNET sizes.

METHODS

A retrospective cohort study was conducted using patient data from Surveillance, Epidemiology, and End Results Program (SEER) database. Variables analyzed included age, tumor size, grade, stage, and lymph node status. Disease-specific survival (DSS) was compared for endoscopic and surgical groups in dNET size strata: 0-0.5, 0.5-1, 1-2, 2-3, and > 3 cm. Kaplan-Meier and multivariable Cox proportional hazards models were used for survival analysis.

RESULTS

The study included 465 patients, with 124 (26.7%) undergoing surgical resection. The average age was 61.9 years, and tumor sizes ranged from 0.1 to 10.5 cm. Endoscopic resection had 40.5% of tumors between 0 and 0.5 cm, while surgery had only 21% (p < 0.001). In the surgical cohort, 79.8% had grade 1 tumors compared to 88.3% in the endoscopy group (P = 0.024). Among surgically resected cases, 48.4% (60 patients) had lymph node involvement. Age, tumor size, grade, and stage did not significantly predict survival after surgical resection. Stratified by tumor size, no difference in DSS was observed between surgery and endoscopy groups.

CONCLUSIONS

Endoscopic resection demonstrated similar survival outcomes to surgical resection across dNET sizes in this national analysis. Given the risks and the lack of survival benefits for surgery, endoscopic resection may be beneficial for both small and large tumors. Further studies are warranted to validate the current NCCN guidelines.

Prognostic differences in grading and metastatic lymph node pattern in patients with small bowel neuroendocrine tumors

PURPOSE

Neuroendocrine tumors of the small intestine (si-NET) describe a heterogenous group of neoplasms. Based on the Ki67 proliferation index si-NET are divided into G1 (Ki67 < 2%), G2 (Ki67 3-20%) and rarely G3 (Ki67 > 20%) tumors. However, few studies evaluate the impact of tumor grading on prognosis in si-NET. Moreover, si-NET can form distinct lymphatic spread patterns to the mesenteric root, aortocaval lymph nodes, and distant organs. This study aims to identify prognostic factors within the lymphatic spread patterns and grading.

METHODS

Demographic, pathological, and surgical data of 208 (90 male, 118 female) individuals with si-NETs treated at Charité University Medicine Berlin between 2010 and 2020 were analyzed retrospectively.

RESULTS

A total of 113 (54.5%) specimens were defined as G1 and 93 (44.7%) as G2 tumors. Interestingly, splitting the G2 group in two subgroups: G2 low (Ki67 3-9%) and G2 high (Ki67 10-20%), displayed significant differences in overall survival (OS) (p = 0.008) and progression free survival (PFS) (p = 0.004) between these subgroups. Remission after surgery was less often achieved in patients with higher Ki67 index (> 10%). Lymph node metastases (N +) were present in 174 (83.6%) patients. Patients with isolated locoregional disease showed better PFS and OS in comparison to patients with additional aortocaval and distant lymph node metastases.

CONCLUSION

Lymphatic spread pattern influences patient outcome. In G2 tumors, low and high grading shows heterogenous outcome in OS and PFS. Differentiation within this group might impact follow-up, adjuvant treatment, and surgical strategy.

Small bowel neuroendocrine tumours - casting the net wide

PURPOSE OF REVIEW

Our aim is to provide an overview of small bowel neuroendocrine tumours (NETs), clinical presentation, diagnosis algorithm and management options. We also highlight the latest evidence on management and suggest areas for future research.

RECENT FINDINGS

Dodecanetetraacetic acid (DOTATATE) scan can detect NETs with an improved sensitivity than when compared with an Octreotide scan. It is complimentary to small bowel endoscopy that provides mucosal views and allows the delineation of small lesions undetectable on imaging. Surgical resection is the best management modality even in metastatic disease. Prognosis can be improved with the administration of somatostatin analogues and Evarolimus as second-line therapies.

SUMMARY

NETs are heterogenous tumours affecting most commonly the distal small bowel as single or multiple lesions. Their secretary behaviour can lead to symptoms, most commonly diarrhoea and weight loss. Metastases to the liver are associated with carcinoid syndrome.

Prognostic Effect of Lymph Node Metastases and Mesenteric Deposits in Neuroendocrine Tumors of the Small Bowel

Well-differentiated, low-grade neuroendocrine tumors (NETs) are the most frequent tumor types of the small bowel. Despite their generally indolent growth patterns and grade, these tumors tend to metastasize; indeed, at presentation, approximately 50% show nodal metastases and 30% of patients have distant metastases, even though they potentially show long survival. Little is available in the literature concerning the optimal nodal yield in small-bowel resections, and the clinical significance of nodal metastases and lymph node ratio (LNR) at this site is still debated. The aim of this review, through a systematic literature search, is to explore and analyze data regarding nodal status, adequacy of lymphadenectomy, and LNR on the prognosis of small bowel NETs using defined end points (progression-free survival, recurrence-free survival, and overall survival). Some surgical series have demonstrated that extended regional mesenteric lymphadenectomy, together with primary tumor resection, is associated with improved patient survival, and LNR is proving a prognostically important parameter. The new feature of mesenteric tumor deposits (MTDs; neoplastic deposits found in the mesenteric perivisceral adipose tissue that are not LN associated) seems to be a better prognostic predictor in small-bowel NETs compared to nodal metastases, and this feature is explored and critiqued in this review. In particular, increasing number of tumor deposits is correlated with increased risk of disease-specific death, and MTDs seem to correlate with peritoneal carcinomatosis.

Surgical Treatment of Neuroendocrine Tumors of the Terminal Ileum or Cecum: Ileocecectomy Versus Right Hemicolectomy

BACKGROUND

Simple ileocecectomy and right hemicolectomy are two potential operative approaches to treat patients with neuroendocrine neoplasm in the terminal ileum and/or cecum (IC-NENs). We sought to define the long-term outcome of patients undergoing ileocecectomy versus right hemicolectomy for IC-NENs, as well as characterize number of nodes evaluated and lymph node metastasis (LNM) associated with each procedure.

METHODS

Patients who underwent curative-intent resections for IC-NENs between 2000 and 2016 were identified from a multi-institutional database. The clinicopathologic characteristics, surgical procedures, and the overall (OS) and recurrence-free survival (RFS) were compared among patients who underwent formal right hemicolectomy versus ileocecectomy only.

RESULTS

Among 127 patients with IC-NENs, median size of the largest tumor size was 2.0 (IQR 1.2-2.9) cm; 35 (27.6%) patients had multiple lesions. At the time of surgery, 93 (73.2%) patients underwent a right hemicolectomy, whereas 34 (26.8%) had ileocecectomy only. Every patient had a lymph node dissection (LND) with a median number of 16 (IQR 12-22) nodes evaluated. A majority (n = 110, 86.6%) of patients had LNM with a median number of 3 (IQR 2-5) LNM. Patients who underwent hemicolectomy had more lymph nodes evaluated versus patients who had an ileocecectomy only (median, 18 vs. 14, p = 0.004). Patients who underwent formal right hemicolectomy versus ileocecectomy had a similar OS (median OS, 101.9 vs. 144.5 months, p = 0.44) and RFS (median RFS, 70.3 vs. not attained, p = 0.80), respectively.

CONCLUSIONS

Ileocecectomy had similar long-term outcomes versus right hemicolectomy in treatment of IC-NENs despite a difference in the lymph node harvest.

Evaluation of Pathologic Prognostic Factors in Neuroendocrine Tumors of the Small Intestine

The precise contributions of histopathologic features in the determination of stage and prognosis in small intestinal neuroendocrine tumors (NETs) are still under debate, particularly as they pertain to primary tumor size, mesenteric tumor deposits (TDs), and number of regional lymph nodes with metastatic disease. This single-institution series reviewed 162 patients with small bowel NETs (84 females, mean age: 60.3±12.0 y). All cases examined (100%) were immunoreactive for both chromogranin A and synaptophysin. Primary tumor size >1 cm (P=0.048; odds ratio [OR]=3.06, 95% confidence interval [CI]: 1.01-9.24) and lymphovascular invasion (P=0.007; OR=4.85, 95% CI: 1.53-15.40) were associated with the presence of lymph node metastasis. Conversely, TDs (P=0.041; OR=2.73, 95% CI: 1.04-7.17) and higher pT stage (P=0.006; OR=4.33, 95% CI: 1.53-12.28) were associated with the presence of distant metastasis (pM). A cutoff of ≥7 positive lymph nodes was associated with pM (P=0.041), and a thusly defined modified pN stage (pNmod) significantly predicted pM (P=0.024), compared with the prototypical pN (cutoff of ≥12 positive lymph nodes), which did not. Over a median follow-up of 35.7 months, higher pNmod (P=0.014; OR=2.15, 95% CI: 1.16-3.96) and pM (P<0.001; OR=11.00, 95% CI: 4.14-29.20) were associated with disease progression. Proportional hazards regression showed that higher pNmod (P=0.020; hazard ratio=1.51, 95% CI: 1.07-2.15) and pM (P<0.001; hazard ratio=5.48, 95% CI: 2.90-10.37) were associated with worse progression-free survival. Finally, Kaplan-Meier survival analysis demonstrated that higher pNmod (P=0.003), pM (P<0.001), and overall stage group (P<0.001) were associated with worse progression-free survival, while higher pM also predicted worse disease-specific survival (P=0.025). These data support requiring either chromogranin or synaptophysin, but not both, for small bowel NET diagnosis, the current inclusion of a 1 cm cutoff in primary tumor size and the presence of TDs in staging guidelines, and would further suggest lowering the cutoff number of positive lymph nodes qualifying for pN2 to 7 (from 12).

Surgical Principles in the Management of Lung Neuroendocrine Tumors: Open Questions and Controversial Technical Issues

OPINION STATEMENT

Primary neuroendocrine tumors (NETs) of the lung represent a heterogeneous group of malignancies arising from the endocrine cells, involving different entities, from well differentiated to highly undifferentiated neoplasms. Because of the predominance of poorly differentiated tumors, advanced disease is observed at diagnosis in more than one third of patients making chemo- or chemoradiotherapy the only possible treatment. Complete surgical resection, as defined as anatomical resection plus systematic lymphadenectomy, becomes a reliable curative option only for that little percentage of patients presenting with stage I (N0) high-grade NETs. On the other hand, complete surgical resection is considered the mainstay treatment for localized low- and intermediate-grade NETs. Therefore, in the era of the mini-invasive surgery, their indolent behavior has suggested that parenchyma-sparing resections could be as adequate as the anatomical ones in terms of oncological outcomes, leading to discuss about the correct extent of resection and about the role of lymphadenectomy when dealing with highly differentiated NETs.

[Gastroenteropancreatic neuroendocrine tumors]

Neuroendocrine tumors (NET), or more generally neuroendocrine neoplasms (NEN), represent a very heterogeneous group of rare tumors with varying location which are only defined by their endocrine biology and secretion of synaptophysin and chromogranin A. They originate from mesoderm-derived stem cells. In the last few years, the incidence and prevalence of NEN have been steadily increasing. Classification is based on the affected organ, the proliferation rate and presence or absence of hormone production with typical symptoms. Diagnosis and treatment of these tumors is therefore very specific and requires an interdisciplinary approach. Treatment options include endoscopic or surgical resection, drug therapy for control of symptoms and proliferation, locoregional therapy and radionuclide therapy. Guidelines with algorithms for diagnostic workup and treatment are constantly updated.

Optimal Cut-Off Values of the Positive Lymph Node Ratio and the Number of Removed Nodes for Patients Receiving Resection of Bronchopulmonary Carcinoids: A Propensity Score-Weighted Analysis of the SEER Database

Background

Although lymph node dissection (LND) has been commonly used for patients with bronchopulmonary carcinoids (PCs), the prognostic values of the positive lymph node ratio (PLNR) and the number of removed nodes (NRN) remain unclear.

Methods

Patients with resected PCs were identified in the Surveillance, Epidemiology, and End Results (SEER) database (2010–2015). The optimal cut-off values of the PLNR and NRN were determined by X-tile. The inverse probability of treatment weighting (IPTW) method was used to reduce the selection bias. IPTW-adjusted Kaplan-Meier curves and Cox proportional hazards models were used to compare the overall survival (OS) and cancer-specific survival (CSS) of patients in different PLNR and NRN groups.

Results

The study included 1622 patients. The optimal cut-off values of the PLNR and NRN for survival were 13% and 13, respectively. In both Kaplan-Meier analysis and univariable Cox proportional hazards regression analysis before IPTW, a PLNR ≥13% was significantly associated with worse OS (HR = 3.364, P<0.001) and worse CSS (HR = 7.874, P<0.001). These findings were corroborated by the IPTW-adjusted Cox analysis OS (HR = 2.358, P = 0.0275) and CSS (HR = 8.190, P<0.001) results. An NRN ≥13 was not significantly associated with worse OS in either the Kaplan-Meier or Cox analysis before or after IPTW adjustment. In the Cox proportional hazards analysis before and after IPTW adjustment, an NRN ≥13 was significantly associated with worse CSS (non-IPTW: HR = 2.216, P=0.013; IPTW-adjusted: HR = 2.162, P=0.024).

Conclusion

A PLNR ≥13% could predict worse OS and CSS in patients with PCs and might be an important complement to the present PC staging system. Extensive LND with an NRN ≥13 might have no therapeutic value for OS and may even have an adverse influence on CSS. Its application should be considered on an individual basis.

Prognostic nomogram based on the metastatic lymph node ratio for gastric neuroendocrine tumour: SEER database analysis

Objective

The prediction of survival of gastric neuroendocrine tumours (g-NETs) is controversial. Prognostic effects of the metastatic lymph node ratio (LNR) in patients with g-NET were explored, and a nomogram was plotted to predict the survival rates of patients.

Methods

A longitudinal study conducted on the basis of the Surveillance, Epidemiology, and End Results database. The association between LNR and survival were investigated by using Pearson correlation and Cox regression. Overall survival (OS) and cancer-specific survival (CSS) rates were predicted with the help of nomograms.

Results

A total of 315 patients with g-NET diagnosed from 2004 to 2015 were included in this study. LNR was discovered to have a negative correlation with OS and CSS (Pearson correlation coefficients: 0.343 (p<0.001) and 0.389 (p<0.001), respectively). The multivariate analyses indicated age, tumour site, differentiation, T staging, M staging, chemotherapy and LNR to be independent prognostic factors for both OS and CSS. Surgery was also a prognostic determinant for CSS (p=0.003). Concordance indices of the nomograms for OS and CSS were higher than those of the TNM classification (0.772 vs 0.730 and 0.807 vs 0.768, respectively). As per the area under the receiver operating characteristic curve, predictive ability of the nomograms for survival of 1, 3 and 5 years was all better than that of TNM classification.

Conclusions

LNR is an independent predictor of g-NETs. The nomograms plotted in this study have a satisfying predictive ability of survival risks and are capable of guiding tailored treatment strategies for patients with g-NET.

How to Manage Small Intestine (Jejunal and Ileal) Neuroendocrine Neoplasms Presenting with Liver Metastases?

PURPOSE OF REVIEW

Small intestinal neuroendocrine neoplasms (siNENs) are slowly growing tumours with a low malignant potential. However, more than half of the patients present with distant metastases (stage IV) and nearly all with locoregional lymph node (LN) metastases at the time of surgery. The value of locoregional treatment is discussed controversially.

RECENT FINDINGS

In stage I to III disease, locoregional surgery was currently shown to be curative prolonging survival. In stage IV disease, surgery may prolong survival in selected patients with the chance to cure locoregional disease besides radical/debulking liver surgery. It may improve the quality of life and may prevent severe local complications resulting in a state of chronic malnutrition and severe intestinal ischaemia or bowel obstruction. Locoregional tumour resection offers the opportunity to be curative or to focus therapeutically on liver metastasis, facilitating various other therapeutic modalities. Risks and benefits of the surgical intervention need to be balanced individually.

Incidence, survival and stage at diagnosis of small intestinal neuroendocrine tumours in Queensland, Australia, 2001-2015

AIM

Multiple studies have observed increasing incidence of small intestinal (SI) neuroendocrine tumours (NETs). The aim of this study was to describe incidence, mortality and survival of SI NETs by sub-site and stage at diagnosis.

METHODS

Data on patients diagnosed with SI NETs between 2001 and 2015 were sourced from the Queensland Oncology Repository. Staging algorithms utilising several data sources were used to calculate stage at diagnosis (localised, regional or metastatic disease).

RESULTS

We identified 778 SI NETs and of those 716 (92%) had either a documented or derived stage. Incidence doubled from 0.68 per 100 000 to 1.42 per 100 000 over the 15-year period. Most common site was ileum (49.1%) and 84.2% were of carcinoid morphology type. Stage at diagnosis was calculated for 91.7% of patients with 28.3% presenting with regional involvement and 23.9% with distant metastasis. Risk factors associated with metastatic disease were jejunal and SI site not otherwise specified, neuroendocrine carcinoma histology and residing in a rural area. Increasing incidence of localised disease and a corresponding reduction in metastatic disease was observed over time. Five-year cause-specific survival for patients diagnosed between 2001 and 2005 was 82.5%, increasing to 93.8% from 2011 to 2015. Survival was lowest for those with metastatic disease (74.2%). Survival increased between 2001 to 2005 and 2011 to 2015 for each disease stage.

CONCLUSIONS

SI NET incidence in Queensland doubled between 2001 and 2015. Survival was high and improved over time.

Prognostic Factors in Curative Resected Locoregional Small Intestine Neuroendocrine Neoplasms

BACKGROUND

Small intestinal neuroendocrine neoplasms (SI-NEN) are rare, and only about 40% of patients are diagnosed without distant metastases. Aim of the study was to identify prognostic factors in patients with potentially curative resected locoregional SI-NEN.

METHODS

Patients with curative resected locoregional SI-NEN (ENETS stages I-III) were retrieved from a prospective data base. Demographic, surgical and pathological data of patients with and without disease recurrence were retrospectively analyzed using univariate and multivariate analysis.

RESULTS

In a 20-year period, 65 of 203 (32%) patients with SI-NEN were operated for stages I-III disease. Thirty-eight (58.5%) patients were men, and the median age at surgery was 59 (range 37-87) years. After median follow-up of 65 months, 14 patients experienced disease relapse median 28.5 (range 6-122) months after initial surgery, of which 2 died due to their disease. Multivariate analysis revealed age ≥ 60 years (HR = 6.41, 95% CI 1.38-29.67, p = 0.017), tumor size ≥ 2 cm (HR = 26.54, 95% CI 4.46-157.62, p < 0.001), lymph node ratio > 0.5 (HR 7.18, 95% CI 1.74-29.74, p = 0.007) and multifocal tumor growth (HR = 6.98, 95% CI 1.66-29.39, p = 0.008) as independent negative prognostic factors and right hemicolectomy compared to segmental small bowel resection (HR = 0.04, 95% CI 0.01-0.24, p < 0.001) as independent protector against recurrence.

CONCLUSION

Patients with locoregional SI-NEN with an age ≥ 60 years, tumor size ≥ 2 cm, lymph node ratio > 0.5 and multiple small bowel tumor foci have an increased risk for recurrence and might benefit from adjuvant treatment. In contrast, right hemicolectomy of ileal SI-NEN seems to reduce the risk of recurrence.

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

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.

Deaths of colon neuroendocrine tumors are associated with increasing metastatic lymph nodes and lymph node ratio

BACKGROUND

Colon neuroendocrine tumors (NETs) are uncommon. Currently, the impact of the number of metastatic lymph nodes (LNs) and lymph node ratio (LNR) on survival has been well investigated in other colon malignancies, but both remain nebulous for patients with colon NETs.

METHODS

Surgically resected patients with histologically proven nonmetastatic colon NETs were queried from the Surveillance, Epidemiology, and End Results database between 1988 and 2011. Patients with lymph nodes involved were investigated and categorized into four LNs-based classifications (≤4, >4-10, >10-13, and >13) or three LNR-based subgroups (≤0.51, >0.51-0.71, and >0.71) according to the threshold, determined by Harrell's C statistic. Univariate and multivariate survival analyses were performed by log-rank test and Cox stepwise regression analysis, respectively.

RESULTS

Eight hundred fifty-one patients met the inclusion criteria. Among them, higher LNR and LNs classification are associated with a worse prognosis. The 10-year NETs-specific survival rate was 78.3% (74.2-82.6%), 61.3% (52.4-71.7%), 40.8% (20.7-80.7%) for patients in the ≤4, >4-10, and 10-13 LNs groups, respectively. When patients were classified with LNR, the observed 10-year NETs-specific survival rate was 79.9% (74.8-85.5%) for ≤0.51, 57.4% (43.8-75.2%) for >0.51-0.71, and 40.0% (31.0-51.5%) for >0.71. In stratified analysis, higher LNs and LNR groups have worse prognosis only in patients with advanced T stage (T3-T4). Regarding stage migration, the LNR-based system did not show superiority to LNs-based classification.

CONCLUSIONS

Current TNM staging classification could be improved by considering the count of metastatic nodes and LNR instead of a simple record of lymph node status (N1 or N0) for colon NETs.

Awareness of a mesenteric mass as a common manifestation of ileal neuroendocrine tumor

Omori et al. reported a case of multiple liver metastases originating from synchronous double cancer of “primary mesenteric neuroendocrine tumor” and rectal cancer. However, the “primary mesenteric neuroendocrine tumor” might be a misrecognition of mesenteric metastasis from ileal neuroendocrine tumor. Ileal neuroendocrine tumor is extremely rare in Japan. Herein, we aim to describe the characteristics of ileal neuroendocrine tumor and mesenteric mass as its common manifestation in reference to their reported case.

A novel stratification of mesenteric mass involvement as a predictor of challenging mesenteric lymph node dissection by minimally invasive approach for ileal neuroendocrine tumors

BACKGROUND AND OBJECTIVES

We classified the extent of mesenteric mass (MM) involvement that predicts challenging mesenteric lymph node dissection (mLND) by minimally invasive surgery (MIS) for ileal neuroendocrine tumors (i-NETs).

METHODS

Patients who underwent surgery for i-NETs were retrospectively reviewed. MM involvement was classified as region-0: no MM; region-1: >2 cm from the origins of the ileocolic artery/vein; region-2: ≤2 cm from the origins; and region-3: more proximal superior mesenteric artery/vein. Logistic regression analysis was used to evaluate the predictive value of MM regions for gross positive mesenteric margin (mR2) and/or conversion among the MIS cohort. The open surgery cohort was used as a reference for mR2 rates.

RESULTS

Of 108 patients, 83 patients (77%) underwent MIS. MMs in region-2 and region-3 were independent risk factors for mR2 and/or conversion (odds ratio [95% confidence interval]: 4.25 [1.17-16.4] and 8.51 × 10⁷ [11.0-], respectively, against regions-0 and 1]. mR2 rates of MIS and open surgery cohorts per region did not differ significantly (4% and 7% for regions-0 and 1; 17% and 25% for region-2; and 100% and 83% for region-3).

CONCLUSIONS

The novel stratification of MM regions was predictive of challenging mLND by MIS. Surgeons should have a low threshold for conversion for MMs in proximal regions.

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.

Value of ileus-prophylactic surgery for metastatic neuroendocrine midgut tumours

Neuroendocrine tumours of the small intestine (SINET) are a rare disease. However, a rising incidence rate and excellent long-term survival, even in the setting of metastatic disease lead to a high prevalence of SINET of up to 11/100.000. At the time of diagnosis, most patients already suffer from metastatic disease. About one third of patients demonstrate localized or regional metastatic disease at time of presentation. For those patients the indication for curative surgery is not debated and 10-year cancer specific survival of almost 90% can be achieved. Due to major limitations of existing studies actually there is no sufficient evidence in favour of ileus-prophylactic palliative surgery for metastatic SINET. Until now the available evidence favouring an ileus-prophylactic palliative small bowel resection for stage IV SI-NET must be weighed against available high-level evidence from randomized trials that showed long-term survival under systemic therapy. Importantly, there is not a single study that indicates surgery for a symptomatic patient should be postponed. Because the majority of patients are symptomatic at the time of diagnosis, the rationale for an ileus-prophylactic palliative surgery is to operate before progression of mesenteric tumour mass and desmoplasia takes place and before intestinal obstruction and ischaemia occurs. To what extent a prophylactic palliative small bowel resection will provide a survival benefit in a situation where the mesenteric tumour mass cannot be resected radically is not clearly addressed by the current level of evidence.

Further Classification for Node-Positive Gastric Neuroendocrine Neoplasms

BACKGROUND

For gastric neuroendocrine neoplasms (GNEN), the current AJCC lymph node (N) stage classifies patients into N0/N1 disease (with/without locoregional nodal metastases); however, this does not account for the number of involved nodes. The objective of this study was to evaluate the prognostic significance of the number of involved locoregional nodes among resected GNEN.

METHODS

The National Cancer Database (2004-2014) was queried for GNEN patients who had undergone partial/total gastrectomy with known nodal status. Nearest-neighborhood grouping was used to identify survival clusters by number of metastatic nodes and to use these groupings to construct a new N classification (pN). External validation was performed using the SEER database. Kaplan-Meier analysis and Cox regression models were used to assess the prognostic strength of the pN classification.

RESULTS

One thousand two hundred seventy-five patients met study inclusion criteria. Patients with 1-6 positive nodes (pN1) demonstrated a distinct survival pattern from patients with > 6 positive nodes (pN2) as well as those with no positive nodes (N0) {5-year OS N0: 80% (95% CI 77-83%) vs. 65% (95% CI 61-69%) vs. 43% (95% CI 33-53%), p < 0.001}. On external validation, the pN classification demonstrated strong discriminatory ability for survival {5-year OS N0: 70% (95% CI 65-75%) vs. pN1:53% (95% CI 46-59%) vs. pN2:18% (95% CI 9-29%), p < 0.001}. On multivariable analysis, the pN classification remained an independent predictor of OS.

CONCLUSIONS

The number of metastatic lymph nodes is an independent prognostic factor in GNEN. Current AJCC N1 disease contains two groups of patients with distinctive prognoses, hence needs to be subclassified into pN1 (1-6 positive lymph nodes) and pN2 (> 6 positive nodes).

Number, not size, of mesenteric tumor deposits affects prognosis of small intestinal well-differentiated neuroendocrine tumors

Mesenteric tumor deposits are an adverse prognostic factor for small intestinal well-differentiated neuroendocrine tumors. Per the American Joint Committee on Cancer (AJCC) Cancer Staging Manual (eighth edition), any mesenteric tumor deposit larger than 2 cm signifies pN2 disease. This criterion has not been critically evaluated as a prognostic factor for small intestinal neuroendocrine tumors, nor have multifocality or histologic features of mesenteric tumor deposits. We evaluated 70 small intestinal neuroendocrine tumors with mesenteric tumor deposits for lesional contour, sclerosis, inflammation, calcification, entrapped blood vessels, and perineural invasion. Ki67 proliferative indices of the largest mesenteric tumor deposit from each case were calculated, and number of tumor deposits and size of the largest deposit were recorded. Associations between these factors (along with patient age, primary tumor Ki67 index, and AJCC stage) and development of liver metastases and overall survival were assessed. Median mesenteric tumor deposit size was 1.5 cm (range: 0.2-7.0 cm); median deposit number was 1 (range: 1-13). Primary and tumor deposit Ki67 indices within a given patient were discordant in 40% of cases but showed similar hazard ratios for disease-specific survival. Size of tumor deposits had no significant effect on prognosis, whether analyzed on a continuous scale or dichotomized using the recommended 2 cm cutoff. In contrast, increasing number of deposits was associated with poor prognosis, with multiple deposits conferring an 8.19-fold risk of disease-specific death compared to a single deposit (P = 0.049). Morphologic features of deposits had no prognostic impact. Size of mesenteric tumor deposits does not affect prognosis in small intestinal neuroendocrine tumor patients; instead, deposit multifocality is associated with shorter disease-specific survival and should be incorporated into future staging criteria.

Curative and palliative surgery in patients with neuroendocrine tumors of the gastro-entero-pancreatic (GEP) tract

The incidence of neuroendocrine tumors (NET) increases with age. Lately, the diagnosis of NET was mainly caused by early detection of small NET (<1 cm) in the rectum and stomach, which are depicted by chance during routine and prophylactic endoscopy. Also in patients with large and metastatic pancreatic and intestinal tumors thorough pathologic investigation with use of different immunohistologic markers discovers more neuroendocrine tumors with low differentiation grade (G2-G3) and more neuroendocrine carcinomas (NEC), nowadays, than in former times. While gastric and rectal NET are discovered as small (<1 cm in diameter) and mainly highly differentiated tumors, demonstrating lymph node metastases in less than 10% of the patients, the majority of pancreatic and small bowel NET have already metastasized at the time of diagnosis. This is of clinical importance, since tumor stage and differentiation grade not only influence prognosis but also surgical procedure and may define whether a combination of surgery with systemic biologic therapy, chemotherapy or local cytoreductive procedures may be used. The indication for surgery and the preferred surgical procedure will have to consider personal risk factors of each patient (i.e. general health, additional illnesses, etc.) and tumor specific factors (i.e. tumor stage, grade of differentiation, functional activity, mass and variety of loco regional as well as distant metastases etc.). Together they define, whether radical curative or only palliative surgery can be applied. Altogether surgery is the only cure for locally advanced NET and helps to increase quality of life and overall survival in many patients with metastatic neuroendocrine tumors. The question of cure versus palliative therapy sometimes only can be answered with time, however. Many different aspects and various questions concerning the indication and extent of surgery and the best therapeutic procedure are still unanswered. Therefore, a close multidisciplinary cooperation of colleagues involved in biochemical and localization diagnostics and those active in various treatment areas is warranted to search for the optimal strategy in each individual patient. How far genetic screening impacts survival remains to be seen. Since surgeons do have a central role in the treatment of NET patients, they have to understand the need for integration into such an interdisciplinary team.

Exploration of the Exact Prognostic Significance of Lymphatic Metastasis in Jejunoileal Neuroendocrine Tumors

BACKGROUND

How to evaluate the prognostic significance of lymphatic metastasis in patients with small bowel (jejunoileal) neuroendocrine tumors (SBNETs) is still not conclusive.

METHODS

Data for patients with SBNETs, but without distant metastasis, were retrieved from the Surveillance, Epidemiology, and End Results database. Recursive partitioning analysis (RPA) was used for classification development by combining examined lymph nodes (ELNs) and lymph node ratio (LNR).

RESULTS

Overall, 1925 patient records were retrieved. Patients with N0 and N1 disease (based on the definition of the European Neuroendocrine Tumor Society [ENETS] staging classification) did not have different OS (p = 0.7867), nor did patients with N0, N1 (< 12 positive nodes), and N2 (≥ 12 positive nodes) disease based on the definition of American Joint Committee on Cancer (AJCC) 8th edition staging classification (p = 0.5276). However, Cox regression analysis indicated that both ELNs (hazard ratio [HR] 0.968, 95% confidence interval [CI] 0.949-0.987; p = 0.0013) and LNR (HR 2.288, 95% CI 1.122-3.682; p = 0.0006) were prognostic factors. Using RPA, we combined ELNs and LNR, and patients were reclassified into three groups (group 1: ELNs ≥ 12, any LNR; group 2: ELNs < 12, LNR < 0.35; group 3: ELNs < 12, LNR ≥ 0.35). Survival analysis and multivariate Cox regression showed that groups 1, 2, and 3 had progressively worse survival. Furthermore, we found that ELNs ≥ 12 could remarkably improve patient survival (p < 0.001).

CONCLUSIONS

The current definition of lymphatic metastasis could not help predict patient survival. Our newly proposed classification of lymphatic metastasis is better than the ENETS and AJCC 8th edition staging classifications in evaluating the prognostic significance of lymphatic metastasis in SBNETs. Systematic resection of lymph nodes (≥ 12) could help improve patient survival.

IMP3 expression in small-intestine neuroendocrine neoplasms: a new predictor of recurrence

PURPOSE

Small-intestine neuroendocrine neoplasms are heterogeneous neoplasms arising from endocrine cells of the intestinal mucosa. Ki-67 is the main determinant of prognosis in neuroendocrine neoplasms. However, the search for new prognostic makers represents a key point with regard to small-intestine neuroendocrine neoplasms. The oncofetal protein IMP3 plays a role in cell growth and its expression has a prognostic value in lung neoplasms.

METHODS

From January 1998 to August 2015, all the consecutive small-intestine neuroendocrine neoplasms patients suitable for surgery were included: 51 patients (32 males, median age 68 years) had small-intestine neuroendocrine neoplasms classified according to the WHO 2010 classification. In all the cases IMP3 expression was evaluated on primary tumors and, when available, on nodal and distant metastases. The medical records and pathological slides of these patients were used to determine the clinical characteristics, pathological diagnoses, and outcome information.

RESULTS

The overall 5-year and 10-year survival rate were 53.9 and 42% respectively. At Cox proportional hazards regression grading was the major factor influencing both OS and progression-free survival at univariate (p = 0.0002 and 0.0051, respectively) and multivariate analysis (p = 0.0004 and 0.0043, respectively). Also IMP3 expression at the nodal metastases resulted a factor significantly associated with progression-free survival at both univariate (p = 0.0066) and multivariate analysis (p = 0.0059, HR 3.58). IMP3 expression did not correlate with the Ki-67 (p = n.s.).

CONCLUSIONS

In this study, IMP3 at the nodal site resulted to be associated with low progression-free survival in small-intestine neuroendocrine neoplasms, independently of the Ki-67 index. We suggest that the integration of IMP3 and Ki-67 would help better stratify the risk of progression in small-intestine neuroendocrine neoplasms.

Lymph Node Metastasis in the Prognosis of Gastroenteropancreatic Neuroendocrine Tumors

OBJECTIVES

This study aimed to determine the prognostic use of the extent of lymph node (LN) involvement in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) by analyzing population-based data.

METHODS

Patients in the Surveillance, Epidemiology, and End Results registry were identified with histologically confirmed, surgically resected GEP-NETs. We divided patients into 3 lymph node ratio (LNR) groups based on the ratio of positive LNs to total LNs examined: 0.2 or less, greater than 0.2 to 0.5, and greater than 0.5. Disease-specific survival was compared according to LNR group.

RESULTS

We identified 3133 patients with surgically resected GEP-NETs. Primary sites included the stomach (11% of the total), pancreas (30%), colon (32%), appendix (20%), and rectum (7%). Survival was worse in patients with LNRs of 0.2 or less (hazard ratio [HR], 1.5; 95% confidence interval [CI], 1.2-2.0), greater than 0.2 to 0.5 (HR, 2.0; 95% CI, 1.6-2.5), and greater than 0.5 (HR, 3.1; 95% CI, 2.5-3.9) compared with N0 patients. Ten-year disease-specific survival decreased as LNR increased from N0 (81%) to 0.2 or less (69%), greater than 0.2 to 0.5 (55%), and greater than 0.5 (50%). Results were consistent for patients with both low- and high-grade tumors from most primary sites.

CONCLUSIONS

Degree of LN involvement is a prognostic factor at the most common GEP-NET sites. Higher LNR is associated with decreased survival.

Improving survival prognostication of gastroenteropancreatic neuroendocrine neoplasms: Revised staging criteria

PURPOSE

Current staging criteria for gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), while useful, have limitations. In this study, we used a population-based registry to evaluate the prognostic utility of the current staging systems and assess whether evidence-based modifications can improve survival predictions.

METHODS

We identified patients with confirmed GEP-NENs from the Surveillance, Epidemiology and End Results registry. We assigned tumour-node-metastasis status according to American Joint Committee on Cancer and European Neuroendocrine Tumor Society criteria. We derived a revised staging classification using Kaplan-Meier methods and Cox regression to assess disease-specific survival and compared the accuracy of potential models based on the Akaike Information Criterion (AIC) and Harrell's C-index. The revised classification was validated in an independent set.

RESULTS

We identified 10,268 patients with GEP-NENs. We found that multiple stages, as determined by current criteria, misclassified patients' prognosis. In particular, stage IIIB (T1-4N1) had overlapping survival with stage IIIA (T4N0). A revised system which reclassifies N1 disease into different stages based on T status (T1-2N1, T3N1 and T4N1) had an improved AIC (difference = 38) and C-index (0.86) compared to current staging. These revisions improved predictions in patients with both low and high-grade tumours from all primary sites. Results also were confirmed across all primary sites in the validation set.

CONCLUSION

Current staging guidelines misclassify the prognosis of N1 patients. Our results suggest that a revised system could lead to better prognostication for GEP-NEN patients. Further validation followed by implementation of these revisions may improve treatment selection and design of clinical trials.

Synchronous Ileal Neuroendocrine Tumor and Ovarian Steroid Cell Tumor Present in a Female With Hyperandrogenism

Well-differentiated neuroendocrine tumors (NET) of the ileum are generally slow-growing tumors with metastatic potential that may cause systemic symptoms from the secretion of serotonin, cortisol, and other biologically active substances. Likewise, steroid cell tumors of the ovary are slow-growing tumors that cause systemic symptoms from the functional production of androgens, estrogens, and other hormones. To the best of our knowledge, synchronous ileal NET and ovarian steroid cell tumors have not been previously reported in the English literature. We present a case of a 59-yr-old woman with 2 primary tumors that were found incidentally: a Stage III (T2N1M0) 1.6 cm well-differentiated NET (NET G2) of the terminal ileum with metastasis to a mesenteric lymph node and a 2.4 cm steroid cell tumor of the left ovary. The patient had suffered from hyperandrogenism for several years before diagnosis of an ovarian steroid cell tumor, but had no symptoms attributable to the NET. From review of the literature, this is the first case description of these 2 primaries arising in the same individual.