Management of early gastrointestinal neuroendocrine neoplasms

Last decade of advances in gastric neuroendocrine tumors: Innovations, challenges, and future directions

BACKGROUND

Gastric neuroendocrine tumors (G-NETs) are rare tumors originating from enterochromaffin-like cells, with an incidence of 0.4 per 100000 annually. There are three main types: (1) Type I, linked to chronic atrophic gastritis and hypergastrinemia, makes up 75%–80% of G-NETs; (2) Type II, associated with Zollinger-Ellison syndrome (ZES) and multiple endocrine neoplasia, comprises 5%; and (3) Type III, sporadic tumors with a higher metastatic potential, accounting for 15%–25%. Diagnosis involves endoscopy, biopsy, and histological examination. Additional methods include serum gastrin testing, immunohistochemistry, and imaging techniques such as computer tomography or magnetic resonance imaging for detecting metastasis. Type I treatment usually involves endoscopic resection (ER), with surgical resection for recurrence. Somatostatin analogs (SSAs) can reduce tumor size, and the prognosis is generally excellent. Type II treatment centers on surgical removal of the gastrinoma, with ER for smaller lesions and SSAs for symptom management. Type III requires surgical resection (partial or total gastrectomy) with lymph node dissection, and possibly chemotherapy. This type has a worse prognosis due to its aggressive nature. Emerging treatments like Peptide Receptor Radionuclide Therapy are promising for advanced cases, and ongoing research into immunotherapies is expanding future treatment options. Regular endoscopic follow-up is crucial to monitor for recurrence or metastasis across all types. Our literature review explores the current perspectives on G-NETs and highlights the importance of further research to improve diagnostic precision and treatment, particularly for those associated with less favorable cases.

AIM

To improve diagnostic precision and treatment, particularly for those associated with less favorable cases.

METHODS

A systematic search was conducted in PubMed, Scopus, and Web of Science until September 2024. Two independent reviewers screened titles, abstracts, and full texts for eligibility based on G-NET treatment in adults. Eligible studies included cohort studies, clinical trials, case series, and case reports, while in vitro, pediatric, and non-English studies were excluded. Relevant data were extracted independently, and disagreements were resolved through discussion. Study quality was assessed using appropriate tools.

RESULTS

G-NETs are rare, classified into three types: (1) Type I; (2) Type II; and (3) Type III. Type I G-NETs, often associated with chronic atrophic gastritis, are typically slow-growing and low-grade, with favorable outcomes following surgical resection. Type II G-NETs arise in hypergastrinemia conditions like multiple endocrine neoplasia and ZES, showing moderate malignancy risk. Type III G-NETs, the most aggressive and least common, present with distant metastases and poor prognosis. Diagnosis relies on endoscopy, imaging, and biomarkers like chromogranin A. Treatment varies by type, ranging from ER to aggressive surgery and chemotherapy for advanced cases. Regular follow-up is essential to monitor recurrence, particularly for type III G-NETs.

CONCLUSION

G-NETs require tailored diagnosis and treatment based on type and stage. Types I and II generally have better prognosis, while types III and IV are linked to poorer outcomes due to invasion and metastasis. Treatment strategies vary from ER for type I to extensive surgery for type III. Emerging therapies, like somatostatin analogs and peptide-receptor radionuclide therapies, show promise in advanced cases. Further research is essential to improve early diagnosis and treatment, particularly for high-risk lesions.

Comparison of endoscopic submucosal dissection and modified endoscopic mucosal resection for rectal neuroendocrine tumors

Although some studies have compared the treatment outcomes between modified endoscopic mucosal resection (m-EMR) and endoscopic submucosal dissection (ESD) for rectal neuroendocrine tumors (NETs), the results are based on the experience of experts from a single high-volume center. This multicenter study aimed to compare the outcomes between m-EMR and ESD for rectal NETs, with emphasis on the operator's level. Data of patients with rectal NETs treated using m-EMR or ESD at seven institutions that included general hospitals in Japan were retrospectively reviewed. Patients treated using m-EMR and those treated using ESD were matched for age, sex, lesion size, lesion location, and operator level through propensity score matching. The treatment outcomes were compared between the two groups. In total 304 patients (m-EMR = 178, ESD = 126) were included, with 218 in the matched groups (m-EMR = 109, ESD = 109). The R0 resection rate was not significantly different between the two groups (90.0% vs. 82.3%, P = .221). However, the procedural time was significantly shorter for the m-EMR group than that for the ESD group (6 vs. 26 min, P < .001). No significant difference in adverse events was observed between the two groups (postprocedure bleeding rate: 5.5% vs. 2.8%, P = .335; perforation rate: 0.9% vs. 0.9%, P = 1.00). Subgroup analysis revealed that the R0 resection rate for the trainees was significantly higher in the m-EMR group than in the ESD group (87.9% vs. 64.5%, P = .017). m-EMR is the preferred technique for the treatment of rectal NETs and should be considered, particularly for the trainees.

Rectal neuroendocrine tumours and the role of emerging endoscopic techniques

Rectal neuroendocrine tumours represent a rare colorectal tumour with a 10 fold increased prevalence due to incidental detection in the era of colorectal screening. Patient outcomes with early diagnosis are excellent. However endoscopic recognition of this lesion is variable and misdiagnosis can result in suboptimal endoscopic resection with subsequent uncertainty in relation to optimal long-term management. Endoscopic techniques have shown particular utility in managing this under-recognized neuroendocrine tumour.

Endoscopic techniques for gastric neuroendocrine tumors: An update

Gastric neuroendocrine neoplasms (gNENs) are a rare type of gastric neoplasm, even if their frequency is increasing according to the latest epidemiologic revisions of the main registries worldwide. They are divided into three main subtypes, with different pathogeneses, biological behaviors, and clinical characteristics. GNEN heterogeneity poses challenges, therefore these neoplasms require different management strategies. Update the knowledge on the endoscopic treatment options to manage g-NENs. This manuscript is a narrative review of the literature. In recent years, many advances have been made not only in the knowledge of both the pathogenesis and the molecular profiling of gNENs but also in the endoscopic expertise towards innovative treatment options, which proved to be less aggressive without losing the capability of being radical. The endoscopic approach is increasingly applied in the field of gastrointestinal (GI) luminal neoplasms, and this is true not only for adenocarcinomas but also for gNENs. In particular, different techniques have been described for the endoscopic removal of suspected lesions, ranging from classical polypectomy (cold or hot snare) to endoscopic mucosal resection (both with "en bloc" or piecemeal technique), endoscopic submucosal dissection, and endoscopic full-thickness resection. GNENs comprise different subtypes of neoplasms with distinct management and prognosis. New endoscopic techniques offer a wide variety of approaches for GI localized neoplasms, which demonstrated to be appropriate and effective also in the case of gNENs. Correct evaluation of size, site, morphology, and clinical context allows the choice of tailored therapy in order to guarantee a definitive treatment.

Resection of primary lesion with chemotherapy improves the survival of patients with metastatic colorectal neuroendocrine carcinoma

OBJECTIVE

To evaluate the effect of resection of primary lesion and chemotherapy on survival of patients with metastatic colorectal neuroendocrine carcinoma (CRNEC).

METHODS

Clinical data of 393 patients with metastatic CRNECs between January 2010 and December 2016 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database, including 171 patients who received resection of primary lesion and 221 patients who did not undergo surgery. With the propensity score matching method 172 non-operated patients were selected as controls. Kaplan-Meier method and Log-rank test were used to evaluate the survival differences, while the prognostic factors were analyzed by Cox proportional-hazards model. Metastatic CRNEC patients from January 2001 to December 2021 in Affiliated Jinhua Hospital, Zhejiang University School of Medicine were selected for validation.

RESULTS

Compared with non-operated patients, patients who received resection had longer cause-specific survival ( P<0.05). Patients with resected positive lymph nodes>8 had a poorer prognosis compared to those with resected positive lymph nodes≤8 ( P<0.05). Multivariate analysis showed that gender, location of primary lesion and treatments were independent risk factors for cause-specific survival in patients with metastatic CRNEC (all P<0.05). For metastatic CRNEC patients with resection of primary lesion, rectal neuroendocrine carcinoma, positive resected lymph nodes≤8 and resection of primary lesion combined with chemotherapy were associated with better cause-specific survival (all P<0.05).

CONCLUSIONS

Patients with metastatic CRNEC may benefit from resection of primary lesion, and resection of primary lesion combined with chemotherapy might be the better strategy for metastatic CRNECs. The number of positive lymph nodes resected is correlated with the prognosis of patients.

Endoscopic techniques for diagnosis and treatment of gastro-entero-pancreatic neuroendocrine neoplasms: Where we are

BACKGROUND

The correct localization of the primary tumor site and a complete histological diagnosis represent the milestones for the proper management of gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs).

AIM

To analyze current evidence on the role of endoscopy in the diagnosis/treatment of GEP-NENs.

METHODS

An extensive bibliographical search was performed in PubMed to identify guidelines and primary literature (retrospective and prospective studies, systematic reviews, case series) published in the last 15 years, using both medical subject heading (MeSH) terms and free-language keywords: gastro-entero-pancreatic neuroendocrine neoplasms; endoscopy; ultrasound endoscopy; capsule endoscopy; double-balloon enteroscopy; diagnosis; therapy; staging.

RESULTS

In the diagnostic setting, endoscopic ultrasonography (EUS) represents the diagnostic gold standard for pancreatic NENs and the technique of choice for the locoregional staging of gastric, duodenal and rectal NENs. The diagnosis of small bowel NENs (sbNENs) has been improved with the advent of video capsule endoscopy and double-balloon enteroscopy, which allow for direct visualization of the entire small bowel; however, data regarding the efficacy/safety of these techniques in the detection of sbNENs are scanty and often inconclusive. From a therapeutic point of view, endoscopic removal is the treatment of choice for the majority of gastric NENs (type 1/2), for well-differentiated localized nonmetastatic duodenal NENs < 1 cm, confined to the submucosa layer and for < 10 mm, stage T1-T2, rectal NENs. EUS-guided pancreatic locoregional ablative treatments have been proposed in recent studies with promising results in order to control symptoms or reduce tumor burden in selected patients.

CONCLUSION

Standard axial endoscopy and EUS still play a pivotal role in several GEP-NENs. Advanced techniques for increasing the rate of R0 resection should be reserved for high-volume referral centers.

Clinical outcomes of endoscopic resection for rectal neuroendocrine tumors: Advantages of endoscopic submucosal resection with a ligation device compared to conventional EMR and ESD

Objectives

Methods

Results

Conclusions

Favorable long-term outcomes of endoscopic resection for nonampullary duodenal neuroendocrine tumor

BACKGROUND AND AIM

The long-term outcomes of endoscopic resection for nonampullary duodenal neuroendocrine tumors are limited. We aimed to clarify it.

METHODS

Consecutive patients with nonampullary duodenal neuroendocrine tumors endoscopically treated at our institute between January 2005 and June 2020 were included in this retrospective study. En bloc and R0 resection rates and adverse events were evaluated as short-term outcomes of endoscopic resection. The 5-year overall and recurrence-free survival rates of patients after endoscopic resection were calculated as long-term outcomes.

RESULTS

Of 34 patients with 34 lesions, 33 patients (97%) underwent endoscopic mucosal resection, and one (3%) underwent endoscopic submucosal dissection. En bloc resection was achieved in 33 lesions (97%). R0 resection was achieved in 20 lesions (59%). The median tumor size was 6 mm (range: 3-13). Thirty-one lesions (91%) and three lesions (9%) were classified as G1 and G2, respectively. Lymphovascular invasion was observed in six lesions (18%). Intraprocedural perforation occurred in four patients (12%) who were conservatively treated with endoscopic closure. All 34 patients were followed up without additional treatment after endoscopic resection, and no recurrence or metastasis developed during the median follow-up period of 47.9 months (range: 9.0-187.1). The 5-year overall survival and recurrence-free survival rates were 87.1% and 100%, respectively.

CONCLUSIONS

Endoscopic resection provided a favorable long-term prognosis for patients with nonampullary duodenal neuroendocrine tumors without lymph node metastasis.

Clinical Outcomes of Endoscopic Treatment for Type 1 Gastric Neuroendocrine Tumor

BACKGROUND

Although the rate of early detection and endoscopic treatment of gastric neuroendocrine tumors (NETs) is steadily increasing, there are insufficient studies on the long-term outcomes of endoscopic treatment. Therefore, we aimed to investigate the clinical features and long-term outcomes of endoscopic treatment for type 1 gastric NETs.

METHODS

Subjects who underwent endoscopic treatment for gastric NETs between March 1997 and December 2015 were included. Clinical features and endoscopic treatment outcomes were retrospectively investigated by reviewing medical records.

RESULTS

In total, 125 subjects underwent endoscopic treatment including forceps biopsy (n = 21), argon plasma coagulation (n = 1), endoscopic mucosal resection (EMR, n = 62), and endoscopic submucosal dissection (ESD, n = 41). In total, 103 patients with 114 lesions, who underwent EMR or ESD, were analyzed to evaluate endoscopic and oncologic outcomes. The rates of en bloc resection in the EMR and ESD groups were 91.5% and 97.7%, respectively. Complete resection rates were significantly higher in the ESD group than in the EMR group; it was also higher in < 1-cm small-sized lesions than in 1-2-cm large-sized lesions. Adverse events were similar between the two groups. During a median follow-up period of 63 months, local recurrence rates were 6.5% and 2.4% in the EMR and ESD groups, respectively, and the disease-free survival rate did not differ significantly between the groups.

CONCLUSION

Endoscopic treatment for type 1 gastric NETs less than 2 cm in diameter and confined to mucosal and submucosal layers could be an effective and safe treatment strategy based on the favorable long-term outcome.

Comparison of endoscopic submucosal dissection and transanal endoscopic microsurgery for T1 rectal neuroendocrine tumors: a propensity score-matched study

BACKGROUND AND AIMS

Endoscopic submucosal dissection (ESD) and transanal endoscopic microsurgery (TEM) are the most effective endoscopic resection methods for T1 rectal neuroendocrine tumors (NETs). We aimed to compare the efficacy and safety of ESD and TEM for rectal NETs ≤20 mm.

METHODS

Patients with rectal NETs ≤20 mm who underwent ESD or TEM were enrolled in this retrospective observational study. ESD and TEM groups were matched for pathologic tumor size and EMR history. We evaluated between-group differences in R0 resection rate, adverse event rate, procedure time, and hospital stay.

RESULTS

We included 285 patients (ESD = 226, TEM = 59) in the final cohort, with 104 patients in the matched groups (ESD = 52, TEM = 52). The R0 resection rate was significantly higher for TEM (ESD 71.2% vs TEM 92.3%, P = .005). However, the median procedure time (ESD 22 [range, 11-65] vs TEM 35 [17-160] minutes, P < .001) and hospital stay (ESD 2.5 range 1-5] vs TEM 4 [3-8] days, P < .001) were significantly shorter for ESD. In the subgroup analysis of patients divided by tumor size <10 mm (ESD = 218, TEM = 49) and 10 to 20 mm (ESD = 8, TEM = 10)], there was no significant between-group difference in the R0 resection rate (83.5% vs 93.9%, P = .063 and 37.5% vs 80%, P = .145, respectively) or the rate of recurrence.

CONCLUSIONS

Although TEM showed a better overall R0 resection rate for rectal NETs ≤20 mm, ESD could be a viable treatment modality concerning adverse events, procedure time, and hospital stay for rectal NETs <10 mm with similar R0 resection rates in comparison with TEM.

Synchronous multiple primary malignant neoplasms: a case report of malignant peritoneal mesothelioma and neuroendocrine rectal tumor

We report a rare case of synchronous malignant peritoneal mesothelioma of the biphasic histological type and neuroendocrine tumor (NET) of the rectum without history of asbestos exposure. During 2 years since manifestation of the disease the patient underwent 3 cytoreductive surgeries (CRS): removal of the tumor of the sigmoid mesentery, resection of the rectosigmoid junction completeness of cytoreduction (CC) 0 (2017), omentectomy and partial parietal peritonectomy CC-0 (2017), atypical resection of S2, S4, S5 liver, the removal of the abdominal tumor with left-sided en-block hemicolectomy, partial parietal peritonectomy, argon-plasma coagulation of tumor foci on the mesentery of the small intestine CC-2 (2018) and Transanal Minimally Invasive Surgery-removal of neuroendocrine rectal tumor (2017). The patient underwent hyperthermic intraperitoneal chemotherapy (HIPEC) twice (during 2nd and 3rd CRS). Different regimens of HIPEC were performed: cisplatin + doxorubicin (2017) and metamycin C (2018). The patient received 4 courses of adjuvant chemotherapy with cisplatin plus pemetrexed in 2017 and 3 courses of the chemotherapy with gemcitabine and carboplatin plus bevacizumab in 2018. The patient survived 21 months after the detection of malignant peritoneal mesothelioma in 2017 and died 4 months after the last cytoreductive surgery from the progression of the disease. Histological subtype of MPMP remains important factor in the prognosis of the disease even on the early stages though patient had received the most aggressive variant of special treatment. Minimally invasive treatment tactics of NET demonstrated clinical effectiveness.  

Endoscopic Treatment of Gastric and Duodenal Neuroendocrine Tumors: Present and Future

Gastric and duodenal neuroendocrine tumors (NETs) are not common; however, there is an increase in the incidence due to increased use of endoscopy. Endoscopic treatment has been applied to treat small NET G1 in the stomach and duodenum. For the endoscopic treatment of NETs, it is necessary to evaluate tumor size, depth of invasion, and lymphatic and distant metastasis. This article will review the current knowledge concerning the endoscopic treatment of gastric and duodenal neuroendocrine tumors.

Comparison of conventional and modified endoscopic mucosal resection methods for the treatment of rectal neuroendocrine tumors

BACKGROUND/AIM

Small rectal neuroendocrine tumors (NETs) confined to the submucosa are endoscopically resectable. Because most rectal NETs are submucosal tumors, conventional endoscopic mucosal resection (cEMR) may not result in a complete resection. This study investigated whether modified EMRs, namely endoscopic submucosal resection with ligation (ESMR-L), EMR with precutting (EMR-P), and strip biopsy are superior to cEMR for achieving histologically complete resection (HCR) of rectal NETs.

METHODS

Medical records of 215 patients who were treated with endoscopic resections for rectal NETs between January 2011 and July 2019 were retrospectively enrolled. Of the patients, 110, 33, 29, and 43 underwent cEMR, ESMR-L, EMR-P, and strip biopsy, respectively. For each method, HCR and en bloc resection rates, procedure times, and complication rates were measured.

RESULTS

HCR was achieved with cEMR, EMR-P, ESMR-L, and strip biopsies for 74.5%, 90.9%, 93.1%, and 90.7% of cases, respectively. The HCR rate for cEMR was inferior to those of the modified EMRs (p = 0.045 for cEMR vs. EMR-P; p = 0.031 for cEMR vs. ESMR-L; p = 0.027 for cEMR vs. strip biopsy). Among the three modified EMRs, there was no significant difference in achieving HCR (p = 1.000). En bloc resection (p = 0.096) and complication rates (p = 0.071) were not significantly different among the four EMR methods, although EMR-P required the longest procedure time (p = 0.000).

CONCLUSIONS

All three modified EMRs are superior to cEMR and are equally effective for achieving HCR of rectal NETs.

A novel risk-scoring system for predicting lymph node metastasis of rectal neuroendocrine tumors

AIM

Although rectal neuroendocrine tumors (NETs) are considered to be rare low-grade malignancies when lymph node metastasis (LNM) is present, their degree of malignancy is comparable to that of colorectal cancer (CRC). However, it remains unclear as to which patients require radical lymph node dissection. The aim of this study was to elucidate the risk factors for LNM and develop a risk-scoring system for LNM to help determine appropriate therapeutic approaches.

METHODS

In this study, we examined 103 patients with rectal NETs who underwent local resection (n = 55) or radical resection with LN dissection (n = 48). We evaluated each pathological feature, including the depth of submucosal invasion (SM depth) and tumor budding grade.

RESULTS

According to our univariate analyses and previous reports, the significant five risk factors for LNM were weighted with point values: 2 points for tumor size ≥ 15 mm and muscularis invasion, and 1 point each for SM depth ≥ 2000 µm, positive lymphovascular invasion, budding grade 3, and vertical margin. The area under the receiver operating curve for the scoring system was 0.899 (95% CI: 0.843-0.955). When a score of 2 was used as the cut-off value, the sensitivity and specificity for the prediction of LNM were 100% and 72.1%, respectively.

CONCLUSIONS

The risk-scoring system for LNM of rectal NETs showed high diagnostic performance. Using this risk-scoring system, it is possible to predict the risk of LNM and thereby potentially avoid unnecessary surgery. Further prospective external validation studies should be performed. The study was registered in the Japanese Clinical Trials Registry as UMIN000036658.

A Modified Duodenal Neuroendocrine Tumor Staging Schema Better Defines the Risk of Lymph Node Metastasis and Disease-free Survival

Duodenal neuroendocrine tumors are rare but increasing in incidence and optimal management is hindered by lack of duodenum-specific staging. Duodenal carcinoids were identified in the Surveillance, Epidemiology and End Results tumor registry. Depth of invasion was defined as limited to lamina propria (LP), invading muscularis propria (MP), through muscularis propria (TMP), and through serosa (S). Nine hundred forty-nine patients were identified with majorities being male (57%), white (70%), and node-negative (87%). Tumor size (cm) was less than 1, 47 per cent; 1 to 2, 35 per cent; and greater than 2, 8 per cent with 76 per cent LP. Lymph node (LN) involvement was associated with age, depth of invasion (LP 4%, MP 28%, TMP 54%, and S 57%) and size (less than 1 cm, 3%; 1 to 2 cm, 13%; and greater than 2 cm, 40%). Using the current T staging, LN involvement was: T1 (LP) 2 per cent, T2 (MP or greater than 1 cm) 13 per cent, T3 (TMP) 54 per cent, and T4 (S) 57 per cent. We reclassified current T1 to T1a and current T2 stage to T1b (1 to 2 cm and LP) and T2 (MP or greater than 2 cm). LN metastasis for T1b tumors was 4.7 per cent compared with 20.8 per cent for T2. The resulting TNM classification better defines 5-year disease-specific survival. Our modified staging schema identifies a low-risk group (T1a and T1b) that may be considered for local therapy.

Label-free identification of early gastrointestinal neuroendocrine tumors via biomedical multiphoton microscopy and automatic image analysis

At present, early diagnosis and treatment is the most effective way to treat early gastrointestinal neuroendocrine tumors. Therefore, we attempted to carry out multiphoton imaging of early neuroendocrine tumors because of its ability to label-free image tissue microstructure at the cellular level. Imaging results show that this imaging technique can quickly identify the histopathological changes in mucosa and submucosa caused by tumor invasion. Furthermore, we performed automatic image analysis on SHG images and extracted two optical diagnostic features-collagen density and average intensity, and also found obvious differences in the density as well as average intensity of collagen fibers in tumor microenvironment using a series of quantitative analysis. These findings may further facilitate the development of multiphoton microscopic imaging technique for clinical use.

Response and relapse rates after treatment with long-acting somatostatin analogs in multifocal or recurrent type-1 gastric carcinoids: A systematic review and meta-analysis

BACKGROUND

Type-1 gastric neuroendocrine tumors represent a recurring disease and long-acting somatostatin analogs can inhibit both gastrin release and endocrine cell proliferation. The efficacy and timing of this treatment are still unclear. We performed a systematic review of the literature to clarify the role of somatostatin analog treatment in type-1 gastric neuroendocrine tumors.

METHODS

A computerized literature search was performed using relevant keywords to identify all the pertinent articles published in the last 15 years.

RESULTS

Eight studies were included in this systematic review on somatostatin analogs in type-1 gastric neuroendocrine tumors. A complete response rate ranged from 25-100%. When only the six prospective studies were considered, no significant heterogeneity was observed, and the pooled cumulative complete response rate was 84.5% (confidence interval 73.8-92.8). Three studies evaluated the type-1 gastric neuroendocrine tumor recurrence, with a cumulative relapse rate of 30.2% (confidence interval 13.1-50.6) after 34 months.

CONCLUSION

Somatostatin analogs, namely lanreotide and octreotide, have an excellent response rate, with a good safety profile in selected type-1 gastric neuroendocrine tumors, which cannot be safely managed by endoscopic follow-up or resection due to multiple or frequently recurring disease. After therapy discontinuation, the cumulative relapse rate observed after a median 34-month follow-up was relatively high (30.2%).

Surgical resection for duodenal neuroendocrine neoplasia: Outcome, prognostic factors and risk of metastases

BACKGROUND

Clinical management of duodenal neuroendocrine neoplasms (dNEN) is controversial. The aim of this study was to assess the outcome of surgical management and to identify risk factors for metastatic disease.

METHODS

Patients undergoing surgery for dNEN were retrospectively analysed. Clinicopathologic features, perioperative outcome and survival were assessed. A literature review with focus on risk factors for metastatic disease was additionally performed.

RESULTS

24 patients were identified. Out of 22 patients presenting with their primary tumour, 20 patients underwent curative resection and 18 patients received curative resection with systematic lymphadenectomy. 17 patients underwent formal oncological resection. Surgical mortality was 1 out of 24 patients. The 5-year overall survival rate was 67% in the entire cohort, 71% in patients undergoing resection for their primary tumour, 72% for patients undergoing curative resection with systematic lymphadenectomy, 75% for pN0 and 70% for pN1 tumours. Lymph node metastases were identified in 15 patients undergoing systematic lymphadenectomy, including 9 of 14 patients with tumours smaller than 2 cm, and 6 of 10 patients with G1 tumours. Literature review confirmed a high risk of metastases in small (58%) or G1 (24%) tumours. Tumour grade and angioinvasion were significantly associated with overall and disease-free survival.

CONCLUSION

Even well differentiated or small dNEN harbour a considerable risk of metastases. These data challenge the concepts of surveillance, local resection and endoscopic management for dNEN based on size and grading. Angioinvasion was identified as a strong negative predictor of overall and disease-free survival in dNEN.

Poorly differentiated neuroendocrine rectal carcinoma with uncommon immune-histochemical features and clinical presentation with a subcutaneous metastasis, treated with first line intensive triplet chemotherapy plus bevacizumab FIr-B/FOx regimen: an experience of multidisciplinary management in clinical practice

Background

Neuroendocrine tumors (NETs) are heterogeneous, widely distributed tumors arising from neuroendocrine cells. Gastrointestinal (GI)-NETs are the most common and NETs of the rectum represent 15, 2% of gastrointestinal malignancies. Poorly differentiated neuroendocrine carcinomas of the GI tract are uncommon. We report a rare case of poorly differentiated locally advanced rectal neuroendocrine carcinoma with nodal and a subcutaneous metastasis, with a cytoplasmic staining positive for Synaptophysin and Thyroid Transcription Factor-1.

Case presentation

A 72-year-old male presented to hospital, due to lumbar, abdominal, perineal pain, and severe constipation. A whole-body computed tomography scan showed a mass of the right lateral wall of the rectum, determining significant reduction of lumen caliber. It also showed a subcutaneous metastasis of the posterior abdominal wall. Patient underwent a multidisciplinary evaluation, diagnostic and therapeutic plan was shared and defined. The pathological examination of rectal biopsy and subcutaneous nodule revealed features consistent with small-cell poorly differentiated neuroendocrine carcinoma. First line medical treatment with triplet chemotherapy and bevacizumab, according to FIr-B/FOx intensive regimen, administered for the first time in this young elderly patient affected by metastatic rectal NEC was highly active and tolerable, as previously reported in metastatic colo-rectal carcinoma (MCRC). A consistent rapid improvement in clinical conditions were observed during treatment. After 6 cycles of treatment, CT scan and endoscopic evaluation showed clinical complete response of rectal mass and lymph nodes; patient underwent curative surgery confirming the pathologic complete response at PFS 9 months.

Discussion and conclusions

This case report of a locally advanced rectal NEC with an unusual subcutaneous metastasis deserves further investigation of triplet chemotherapy-based intensive regimens in metastatic GEP NEC.

Endoscopic, transanal, laparoscopic, and transabdominal management of rectal neuroendocrine tumors

Rectal neuroendocrine tumors (RNET) are rare tumors but their prevalence is constantly increasing due to a prolonged survival and rising incidence related to a growing number of colonoscopies and improved knowledge. Their main prognostic determinant is tumor stage. While most RNET are localized, their management should be tailored depending on the presence or absence of the factors predictive of lymph-node metastases including tumor size, endoscopic aspect, T stage, grade and lymphovascular invasion. Endoscopic ultrasonography is the most relevant technique for locoregional assessment. Low-risk RNET can be treated using advanced endoscopic resection techniques or transanal endoscopic microsurgery, in expert centers because they require technicity and experience. Conversely, radical surgery with lymphadenectomy should be proposed in the presence of any pejorative factor. The long-term evolution of RNET remains to be specified, and prospective studies should be conducted in order to determine the relevance of the current management strategies.

Endoscopic management of 345 small rectal neuroendocrine tumours: A national study from the French group of endocrine tumours (GTE)

Introduction

Small rectal neuroendocrine tumours are good candidates for endoscopic resection provided that complete pathological resection (R0) is obtained and their risk of metastatic progression is low. We conducted a large multicentre nationwide study to evaluate the outcomes of the management of non-metastatic rectal neuroendocrine tumours ≤2 cm diagnosed endoscopically.

Patients and methods

The medical records, the endoscopic and pathological findings of patients with non-metastatic rectal neuroendocrine tumours ≤2 cm managed from January 2000-June 2018 in 16 French hospitals, were retrospectively analysed. The primary objective was to describe the proportion of R0 endoscopic resections.

Results

A total of 329 patients with 345 rectal neuroendocrine tumours were included, 330 (96%) tumours were managed by local treatments: 287 by endoscopy only and 43 by endoscopy followed by transanal endoscopic microsurgery. The final endoscopic R0 rate was 134/345 (39%), which improved from the first endoscopy (54/225, 24%), to the second (60/100, 60%) and the third endoscopy (20/26, 77%). R0 was associated with endoscopic technique (90% for advanced techniques, 40% for mucosectomy and 17% for polypectomy), but not with tumour or patient characteristics. Twenty patients had metastatic disease, which was associated with tumour size ≥10 mm (odds ratio: 9.1, 95% confidence interval (3.5-23.5)), tumour grade G2-G3 (odds ratio: 4.2, (1.5-11.7)), the presence of muscular (odds ratio: ∞, (11.9-∞)) and lymphovascular invasion (odds ratio: 57.2, (5.6-578.9)).

Conclusions

The resection of small rectal neuroendocrine tumours often requires multiple procedures. Training of endoscopists is necessary in order to better recognise these tumours and to perform the appropriate resection technique.

Risk factors for lymph node metastasis in duodenal neuroendocrine tumors: A retrospective, single-center study

Duodenal neuroendocrine tumors (NETs) are rare, and risk factors associated with lymph node (LN) metastasis are still not well defined. The aim of this study was to investigate risk factors of LN metastasis in duodenal NETs based on the final histopathologic results and clinical follow-up data.This study included a total of 44 duodenal NETs in 38 patients who underwent endoscopic or surgical resection between January 2008 and December 2015. Diagnosis of duodenal NETs was confirmed based on immunohistochemical staining of chromogranin A, synaptophysin, and CD56; the clinicopathologic records were collected at the time of the initial diagnosis of duodenal NETs.Most duodenal NETs were small (≤1 cm in 33 tumors), World Health Organization (WHO) grade G1 (in 32 tumors), limited to the mucosa and/or submucosa (in 40 tumors), and located at the duodenal bulb (in 32 tumors). Of 44 tumors, lymphovascular invasion was present in 4 (9.1%), and among 38 patients, LN metastasis was detected in 4 (10.5%). LN metastases were significantly associated with the non-bulb location, tumor size >10 mm, tumor invasion into the muscularis propria or deeper, WHO grade G2, and lymphovascular invasion. During the mean follow-up period of 54.5 months (range, 24-123 months), recurrence occurred in 1 patient.Non-bulb location, tumor size >10 mm, invasion beyond the submucosa, WHO grade G2, and lymphovascular invasion are risk factors of LN metastasis in duodenal NETs. These findings can help clinicians choose the appropriate therapeutic modality for duodenal NETs.

Development and characterization of a cancer cachexia model employing a rare human duodenal neuroendocrine carcinoma-originating cell line

Cancer cachexia interferes with therapy and worsens patients' quality of life. Therefore, for a better understanding of cachexia, we aimed to establish a reliable cell line to develop a cachexia model. We recently established and characterized the TCC-NECT-2 cell line, derived from a Japanese patient with poorly differentiated neuroendocrine carcinoma of the duodenum (D-NEC). Subcutaneous xenograft of TCC-NECT-2 cells in mice resulted in tumor formation, angiogenesis, and 20% incidence of body weight (BW)-loss. Subsequently, we isolated a potent cachexia-inducing subline using stepwise selection and designated as AkuNEC. Orthotopic and s.c. implantation of AkuNEC cells into mice led to diminished BW, anorexia, skeletal muscle atrophy, adipose tissue loss, and decreased locomotor activity at 100% incidence. Additionally, orthotopic implantation of AkuNEC cells resulted in metastasis and angiogenesis. Serum IL-8 overproduction was observed, and levels were positively correlated with BW-loss and reduced adipose tissue and muscle volumes in tumor-bearing mice. However, shRNA knockdown of the IL-8 gene did not suppress tumor growth and cachexia in the AkuNEC model, indicating that IL-8 is not directly involved in cachexia induction. In conclusion, AkuNEC cells may serve as a useful model to study cachexia and D-NEC.

Gastric Neuroendocrine Tumors (Carcinoids)

PURPOSE OF REVIEW

The diagnosis of gastric neuroendocrine tumors (NETs) is being made with increased frequency likely as a result of more upper endoscopies being done for unrelated reasons. It is therefore vital that gastroenterologists become familiar with the basic work-up and management of patients found to have these tumors. This review describes the classification, pathophysiology, clinical characteristics, and treatment options of the different gastric NETs.

RECENT FINDINGS

In addition to the three traditional subtypes of gastric NETs, additional cases associated with achlorhydria and appropriate hypergastrinemia may exist. The management of gastric NETs between 1 and 2 cm in size remains controversial and needs to be individualized. Gastric NETs are uncommon but are now diagnosed more frequently. This review highlights the role of hypergastrinemia in their development and the controversies around their management.

Gastric Carcinoids

Gastric carcinoids, formally named gastric neuroendocrine neoplasms (NENs), are derived from enterochromaffin-like cells of the stomach and are increasingly diagnosed. A majority are designated as type I (related to autoimmune gastritis) and type II (related to gastrinoma) neoplasms that develop secondary to gastrin hypersecretion. Types I and II gastric carcinoids are mostly small-sized (1-2 cm), multiple, low-malignancy potential lesions mainly confined to the gastric mucosa/submucosa. These lesions have an indolent course and low metastatic potential. In contrast, type III gastric carcinoids are single, larger-sized (>2 cm), non-gastrin-related lesions that infiltrate the muscular layers associated with local and distant metastases.

Endoscopic treatment of rectal neuroendocrine tumors

The rectum is one of the most frequent location where gastroenteropancreatic neuroendocrine tumors (NETs) are found. With the increasingly widespread availability of colonoscopy screening, the detection rate of rectal NETs has markedly increased, most of which are localized lesions without regional invasion or distant metastasis. Therefore, endoscopic resection is acknowledged as a leading therapeutic approach. Endoscopic mucosal resection, endoscopic submucosal dissection, and transanal endoscopic microsurgery are therapies that have been prevalently applied and technically improved in recent years, which assure increasing complete resection rate and good overall prognosis.

Ki67 labeling index: assessment and prognostic role in gastroenteropancreatic neuroendocrine neoplasms

In 1983, a monoclonal antibody, Ki67, was generated, that labeled the nuclei of proliferating non-neoplastic and neoplastic cells. The name Ki67 derived from the city of Kiel (Ki) where the antibody was produced in the university department of pathology and refers to the number of the original clone (67). Systematic assessment of the proliferative activity of tumors using Ki67 started in the 1990s, when Ki67, which only worked on frozen tissue, was complemented by the antibody MIB-1 that also worked in formalin-fixed tissues. Pancreatic neuroendocrine neoplasms (PanNENs) were the first endocrine tumors whose proliferative activity was assessed with Ki67. This approach was so successful that Ki67 was included as prognostic marker in the 2000 and 2004 WHO classifications of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). In 2010, the WHO classification of GEP-NENs introduced a three-tiered grading, originally proposed by ENETS in 2006 that was mainly based on the Ki67 index. As it has subsequently been shown that the Ki67 index is the most reliable factor in the prognostic evaluation of GEP-NENs, especially of PanNENs, the 2017 WHO classification of PanNENs requires its use and strongly recommends exact assessment of the proportion Ki67-labeled cells as basis for the calculation of the Ki67 index. Problems in assessing the Ki67 index include intertumoral and intratumoral staining heterogeneity and counting methods. Despite such problems, the Ki67 index has emerged as indispensable for the prognostic and therapeutic stratification of the majority of GEP-NENs and can barely be replaced by counting mitoses. In future, however, it can be anticipated that the Ki67 cut-offs experience refinement in relation to the type of tumor, its location, and its response to therapy. It is also possible that the prognostic risk of an individual tumor is calculated for each Ki67 unit and not for an "a priori" fixed Ki67 class.

Endoscopic resection of rectal granular-cell tumor using elastic band ligation

Granular cell tumor (GCT) is a rare neoplasm that develops in the gut's submucosal layer. We report the case of a male with a history of surgically excised colon neoplasm where a rectal polyp was identified during a follow-up endoscopy. The lesion, eventually identified as a GCT, was endoscopically removed by band ligation-assisted mucosectomy. This may be the second report of a colorectal GCT successfully managed using band ligation, and the first one on a rectal GCT excised with this technique.

Early Gastroenteropancreatic Neuroendocrine Tumors: Endoscopic Therapy and Surveillance

Neuroendocrine neoplasias (NEN) of the stomach, duodenum, pancreas, appendix, or rectum that are ≤1 cm in size as well as well-differentiated with World Health Organization grade 1 (G1) can be considered 'early' neuroendocrine tumors; they have a very good prognosis. Regarding prognosis, neuroendocrine tumors (NET) G1 must be distinguished from well-differentiated NET G2 and poorly differentiated neuroendocrine carcinomas (NEC) G3. NET are increasing, with a rise in the age-adjusted incidence in the USA by about 700% in the last 40 years. Earlier diagnosis of NET is one of the main epidemiological changes of clinically detected NEN. The general availability of high-resolution endoscopy and advanced radiological imaging techniques has contributed to a shift in the discovery to smaller-sized (≤10 mm) gastrointestinal and pancreatic NET and earlier tumor stages at diagnosis. Thus, screening colonoscopy is effective in the early diagnosis not only of colorectal adenomas and adenocarcinomas but also of rectal NET. Endoscopic resection is the treatment of choice in NET G1 of the stomach, duodenum (despite gastrinoma), and rectum that are ≤10 mm in size, do not infiltrate the muscularis propria (T1), and do not show angioinvasion (V0, L0). Similarly, histologically proven, early pancreatic NET G1 (≤10 mm) may be managed conservatively by regular surveillance. In contrast, small (≤1 cm) NET G1 of the jejunum or ileum are not 'early' tumors and have to be resected surgically with lymph node dissection.

The Risk Factors for Metastasis in Non-Ampullary Duodenal Neuroendocrine Tumors Measuring 20 mm or Less in Diameter

BACKGROUND/AIMS

The treatment strategy for non-ampullary duodenal neuroendocrine tumors (NAD-NETs) ≤20 mm in diameter has not been established. In this study, we aimed to evaluate the detailed characteristics of NAD-NETs ≤20 mm in diameter to clarify the risk factors of subsequent metastasis.

METHODS

The patients with NAD-NETs ≤20 mm in diameter who had been treated at 12 institutions between 1992 and 2013 were enrolled. Clinical records were retrieved, and histopathological findings of all cases were centrally reviewed by 2 pathologists.

RESULTS

We studied 49 patients with a mean follow-up period of 66.5 months. Thirty-five patients were initially treated with endoscopic resection (ER), and 14 with surgery. A univariate analysis revealed the ORs and 95% CIs of the risk factors for metastasis were lymphovascular invasion (12.5 [2.01-77.9]), multiple tumors (9.75 [1.46-65.4]), a tumor size of 11-20 mm (6.67 [1.21-36.6]), and World Health Organization grade G2 (7.13 [1.16-43.9]). Five-year overall and disease-specific survival rates were 86.1 and 97.2%, respectively.

CONCLUSION

This is the first study to demonstrate the risk factors of metastasis in NAD-NETs ≤20 mm in diameter. These findings may be helpful for determining the appropriate therapeutic approach and the clinical strategy of treatment following ER.

Long-Term Clinical Outcomes of Rectal Neuroendocrine Tumors According to the Pathologic Status After Initial Endoscopic Resection: A KASID Multicenter Study

OBJECTIVES

With advances in diagnostic endoscopy, the detection of rectal neuroendocrine tumors (NETs) has increased. However, clinical outcomes, especially after endoscopic treatment, are still unclear. The aim of this study was to determine the long-term clinical outcomes of endoscopically resected rectal NETs according to the pathologic status after initial resection.

METHODS

In this large, multicenter, retrospective cohort study, we analyzed the medical records of patients who underwent endoscopic resection of rectal NETs and were followed for ≥24 months at 16 university hospitals. The outcomes of interest were local or distant recurrence and metachronous lesions.

RESULTS

On the pathologic assessment of 407 patients, the resection margin status was positive in 76 (18.7%) and indeterminate in 72 (17.7%) patients. Patients whose rectal NETs were diagnosed or suspected as NETs before resection showed a much higher complete resection rate than those whose tumors were resected as polyps and then diagnosed (P<0.001). Fourteen patients received salvage treatment at 1.9±2.8 months after initial treatment. During a median follow-up period of 45.0 months, local recurrence occurred in 3 (0.74%) patients, but there was no recurrence in the lymph nodes or distant organs. Metachronous rectal NETs were diagnosed in 3 (0.74%) patients. According to the pathologic status after initial resection, local recurrence and metachronous lesions occurred in 1 (0.4%) and 2 (0.8%) patients, respectively, in the pathologic tumor-free group, whereas they occurred in 2 (1.4%) and 1 (0.7%) patients, respectively, in the indeterminate group.

CONCLUSIONS

Considering the long-term prognosis including that for recurrences or metachronous lesions, endoscopic resection is an efficient and a safe modality for the treatment of rectal NETs. This treatment may result in favorable clinical outcomes in patients with tumors of indeterminate pathology, as well as in pathologic tumor-free cases after initial resection.

Early diagnosis and treatment of gastrointestinal neuroendocrine tumors

The aim of the present retrospective analysis on the macroscopic appearance and pathological characteristics of gastrointestinal neuroendocrine tumors (NETs) was to investigate methods for their early diagnosis and treatment. A total of 78 patients were divided into submucosal NET and deeper invasion NET groups, according to the depth of tumor invasion exhibited by the patients. The clinicopathological characteristics and survival time of the NET patients were analyzed and compared. The pathological characteristics of the submucosal NETs group were investigated according to the diameter of the tumor (≤5.0 mm, 5.1-10.0 mm or >10.0 mm). The depth of invasion at diagnosis was observed to significantly correlate with histopathological classification, diameter of the tumor, macroscopic appearance, growth pattern, lymphatic-vascular involvement, lymph node (LN) metastasis and distant metastasis. In the submucosal NETs group, high-grade tumors with lymphatic or venule invasion and distant metastasis were associated with an increased risk of nodal metastases. In patients with minute tumors (≤5.0 mm), no lymphatic-vascular involvement, LN or distant metastasis was observed. By contrast, patients with tumors measuring 5.1-10.0 mm in diameter exhibited high lymphatic-vascular involvement and LN metastasis rates (46.2 and 30.8%, respectively). Survival time was significantly longer in patients with submucosal NETs compared with deeper invasion NETs and in patients with NET G1 and NET G2 compared with NEC. The results of the present study indicate that gastrointestinal submucosal NETs are closely associated with a slightly elevated macroscopic type, low-grade tumors and a small diameter. These features may contribute to early diagnosis of gastrointestinal NETs. Therefore, a tumor diameter of <5.0 mm, with slightly elevated macroscopic appearance may indicate an absolute requirement for endoscopic resection, while tumors measuring 5.1-10.0 mm in diameter must be considered carefully.

Neuroendocrine Tumors of the Large Intestine: Clinicopathological Features and Predictive Factors of Lymph Node Metastasis

A new histological classification of neuroendocrine tumors (NETs) was established in WHO 2010. ENET and NCCN proposed treatment algorithms for colorectal NET. Retrospective study of NET of the large intestine (colorectal and appendiceal NET) was performed among institutions allied with the Japanese Society for Cancer of the Colon and Rectum, and 760 neuroendocrine tumors from 2001 to 2011 were re-assessed using WHO 2010 criteria to elucidate the clinicopathological features of NET in the large intestine. Next, the clinicopathological relationship with lymph node metastasis was analyzed to predict lymph node metastasis in locally resected rectal NET. The primary site was rectum in 718/760 cases (94.5%), colon in 30/760 cases (3.9%), and appendix in 12/760 cases (1.6%). Patients were predominantly men (61.6%) with a mean age of 58.7 years. Tumor size was <10 mm in 65.4% of cases. Proportions of NET G1, G2, G3, and mixed adeno-neuroendocrine carcinoma (MANEC) were 88.4, 6.3, 3.9, and 1.3%, respectively. Of the 760 tumors, 468 were locally resected, and 292 were surgically resected with lymph node dissection. Rectal NET showed a higher proportion of NET G1, and colonic and appendiceal NET was more commonly G3 and MANEC. Of the 292 surgically resected cases, 233 NET G1 and G2 located in the rectum were used for the prediction of lymph node metastasis. Lymphatic and blood vessel invasion were independent predictive factors of lymph node metastasis. NET G2 cases showed more frequent lymph node metastasis than that seen in NET G1 cases, but this was not an independent predictor of lymph node metastasis. Of the 98 surgically resected cases <10 mm in size, we found 9 cases with lymph node metastasis (9.2%). All cases were NET G1, and eight of the nine cases were positive either for lymphatic invasion or blood vessel invasion. Using the WHO classification, we found NET in the large intestine showed a tumor-site-dependent variety of histological and clinicopathological features. Risk of lymph node metastasis in rectal NET was confirmed even in lesions smaller than 10 mm. Concordant assessment of vascular invasion will be required to estimate lymph node metastasis in small lesions.

[Neoplasms of the disseminated neuroendocrine cell system of the gastrointestinal tract]

The classification of neuroendocrine neoplasms (NEN) of the gastrointestinal tract and also the pancreas is based on the World Health Organization (WHO) classification from 2010, the site-related TNM stage classification and the clinicopathological characterization. This allows a classification of NEN that is adapted to the individual patient, is of high prognostic relevance and serves the needs of an adequate treatment. This article summarizes the current knowledge on the clinical pathology of gastrointestinal NEN, in order to enable a rapid diagnostic orientation.

[Rectal neuroendocrine tumors: surgical therapy]

The incidence of rectal neuroendocrine tumors (NET) has increased in recent years. Most of these neoplasms are asymptomatic and are diagnosed by colonoscopy screening, which could be one of the reasons for the increasing occurrence. As less than 1 % of rectal NET produce serotonin they are practically never discovered due to a carcinoid syndrome. The current guidelines of the European (ENETS) and North American (NANETS) Neuroendocrine Tumor Societies support clinicians with useful diagnostic and treatment algorithms. The most important criteria for therapy are tumor size and histopathological risk factors for metastases. For well-differentiated rectal neuroendocrine neoplasms < 1 cm, local endoscopic or surgical excision is recommended. Due to the lack of evidence tumors sized 1-2 cm represent a grey area for prognosis and treatment. All NET > 1.5 cm must be excised by radical surgery as low anterior rectal resection or abdominoperineal extirpation with total mesorectal excision (TME). Resectable liver and lung metastases of well-differentiated NETs should be surgically treated with curative intent.

Retrospective analysis of the clinicopathological characteristics of gastrointestinal neuroendocrine neoplasms

The aim of the present study was to analyze and summarize the clinicopathological characteristics and factors affecting prognosis for patients with gastrointestinal neuroendocrine neoplasms (GINENs). Retrospective analysis was conducted on the clinicopathological data of 74 patients who were diagnosed with GINEN, and immunohistochemical methods were used to detect the expression levels of relevant markers [synaptophysin (Syn), chromogranin A (CgA) and Ki-67]. Among the 74 cases with GINEN, there were 39 males and 35 females, with an average age of 56.9 years. There were 32 neoplasms in the rectum, 29 in the stomach, 6 in the colon, 2 in the small intestine and 5 in the appendix. All 74 cases underwent surgical resection. According to the World Health Organization Classification of Tumors of the Digestive System (2010), the diagnosis of the 74 cases showed 41 cases (55.4%) of neuroendocrine tumor (NET; 25 cases of G1 and 16 cases of G2), 21 cases (28.4%) of neuroendocrine carcinoma (NEC) and 12 cases (16.2%) of mixed adenoneuroendocrine carcinoma (MANEC). Additionally, 19 cases had metastasis to lymph nodes. During 10-34 months of follow-up, 15 patients had distant metastasis and 24 patients succumbed, and the accumulative survival rate in 1 or 2 years was 87.8 and 74.3%, respectively. Six factors, namely neoplasm size, depth of invasion, lymph node metastasis, distant metastasis, pathological type and the expression or lack of expression of CgA, significantly affected the survival time of patients. Definitive diagnosis of GINEN mainly relies on pathological diagnosis. GINENs with different histopathological types and grading have different clinicopathological characteristics and prognosis: NETs are mainly early lesions with a good prognosis, whereas NECs and MANECs have high malignancy and strong invasion with a worse prognosis.

Increasing incidence of duodenal neuroendocrine tumors: Incidental discovery of indolent disease?

BACKGROUND

There has been a marked increase in the recognized incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Studies have often combined duodenal neuroendocrine tumors (D-NETs) with other small bowel GEP-NETs. As a result, the natural history and clinical ramifications of these D-NETs is poorly understood.

METHODS

Patients diagnosed with duodenal "carcinoid" tumors from 1983 to 2010 were identified in the Surveillance Epidemiology and End Results tumor registry.

RESULTS

A total of 1,258 patients were identified. The mean age was 64 years. The majority of patients were male (55.6%), white (55.6%), and had stage I disease (66.2%). Patients meeting inclusion criteria were divided into 2 cohorts: (i) era 1 patients diagnosed with GEP-NETs from 1983 to 2005, and (ii) era 2 those diagnosed from 2005 to 2010. There was a clear increase in the incidence rate of D-NETs from 0.27 per 100,000 in 1983 to 1.1 per 100,000 in 2010 (P < .001). Comparison of patients from the different eras revealed that those in era 2 were more likely than era 1 to present with stage I disease (69.9 vs 57.5%; P < .01) and less likely to present with late-stage disease. The 5-year, disease-specific survival improved for era 2 patients compared with era 1 (89.3 vs 85.2%; P = .05); however, multivariate analysis demonstrated that stage but not era was associated with disease-specific survival.

CONCLUSION

Prognosis for D-NETs, in contrast with other small bowel NETs, is excellent. There has been a steady increase in the recognized incidence of D-NETs, coincident with the migration to earlier disease stage and improved disease-specific survival.

CT differentiation of poorly-differentiated gastric neuroendocrine tumours from well-differentiated neuroendocrine tumours and gastric adenocarcinomas

PURPOSE

To evaluate the differential CT features of gastric poorly-differentiated neuroendocrine tumours (PD-NETs) from well-differentiated NETs (WD-NETs) and gastric adenocarcinomas (ADCs) and to suggest differential features of hepatic metastases from gastric NETs and ADCs.

MATERIALS AND METHODS

Our study population was comprised of 36 patients with gastric NETs (18 WD-NETs, 18 PD-NETs) and 38 patients with gastric ADCs who served as our control group. Multiple CT features were assessed to identify significant differential CT findings of PD-NETs from WD-NETs and ADCs. In addition, CT features of hepatic metastases including the metastasis-to-liver ratio were analyzed to differentiate metastatic NETs from ADCs.

RESULTS

The presence of metastatic lymph nodes was the sole differentiator of PD-NETs from WD-NETs (P = .001, odds ratio = 56.67), while the presence of intact overlying mucosa with mucosal tenting was the sole significant CT feature differentiating PD-NETs from ADCs (P = .047, odds ratio = 15.3) For hepatic metastases, metastases from NETs were more hyper-attenuated than those from ADCs.

CONCLUSION

The presence of metastatic LNs and intact overlying mucosa with mucosal tenting are useful CT discriminators of PD-NETs from WD-NETs and ADCs, respectively. In addition, a higher metastasis-to-liver ratio may help differentiate hepatic metastases of gastric NETs from those of gastric ADCs with high accuracy.

KEY POINTS

• Presence of metastatic LNs is a useful differentiator of PD-NETs from WD-NETs. • Intact overlying mucosa with mucosal tenting suggests PD-NETs more than gastric ADCs. • Metastatic LNs are larger in size and greater in necrotic volume in PD-NETs. • Hepatic metastases from gastric NETs are more hyper-attenuated than those from ADCs.

Small duodenal carcinoids: a case series comparing endoscopic resection and autoamputation with band ligation

GOALS

We sought to compare the efficacy and safety of endoscopic ultrasound-guided endoscopic resection (ER) and endoscopic band ligation (EBL) for autoamputation of small duodenal carcinoids.

BACKGROUND

The ideal management of small duodenal carcinoid tumors remains unclear.

STUDY

A retrospective review of duodenal carcinoids over a 10-year period (2002 to 2012) was performed at our tertiary-care teaching hospital. All patients with duodenal carcinoids ≤10 mm in size treated with either ER or EBL were included. The main outcome measurements were the efficacy and safety of endotherapy.

RESULTS

A total of 37 patients with 39 subcentimeter duodenal carcinoids were identified. In the EBL group, the mean (SD) tumor size was 6.7±2.1 mm compared with 6.7±1.7 mm in the ER group (P=0.943). The mean Ki-67 index was ≤2% in specimens available for histologic analysis in both groups (16/23 EBL and 15/16 ER). The positive deep margin rate in the ER group was 68.8%. Residual carcinoid tumor cells were detected on follow-up biopsies in 1 patient after EBL, and 2 patients after ER. All underwent subsequent successful endotherapy. No adverse events occurred in the EBL group compared with an 18.8% adverse event rate in the ER group (P=0.066).

CONCLUSIONS

Endoscopic ultrasound-guided EBL is a safe, effective method for removal of small superficial duodenal carcinoids and seems to be a lower risk alternative to conventional ER with cautery.

Current concepts in the diagnosis and management of type 1 gastric neuroendocrine neoplasms

The vast majority of gastrin-related gastrointestinal neuroendocrine neoplasms (GI-NENs) develop in the context of chronic atrophic gastritis (type 1), a condition closely related to autoimmune thyroid diseases. These neoplasms are defined as gastric NENs type 1 (GNEN1) and have recently been shown to constitute the commonest GI-NENs in a prospective study. GNEN1s are usually multiple and follow a relative indolent course, raising questions regarding the extent that such patients should be investigated and the appropriate therapeutic interventions needed. Recently, a number of consensus statements and guidelines have been published from various societies dealing with the diagnosis and management of GI-NENs. Endocrinologists are among the many different medical specialties involved in GNEN1s diagnosis and management. However, despite recent advances, few randomized trials are available, and thus existing evidence remains relatively weak compared to other malignancies. The purpose of this review is to provide recent evidence along with currently employed modalities addressing the diagnosis, management, long-term follow-up and potential comorbidities of GNEN1s.

Endoscopic biopsy in gastrointestinal neuroendocrine neoplasms: a retrospective study

BACKGROUND

Gastrointestinal neuroendocrine neoplasms (GI-NENs) are often located in the deep mucosa or submucosa, and the efficacy of endoscopic biopsy for diagnosis and treatment of GI-NENs is not fully understood.

OBJECTIVE

The current study analyzed GI-NENs, especially those diagnosed pathologically and resected endoscopically, and focused on the biopsy and cold biopsy forceps polypectomy (CBP) to analyze their roles in diagnosing and treating GI-NENs.

METHODS

Clinical data of all GI-NENs were reviewed from January 2006 to March 2012. Histopathology was used to diagnose GI-NENs, which were confirmed by immunohistochemistry.

RESULTS

67.96% GI-NENs were diagnosed pathologically by endoscopy. Only 26.21% were diagnosed pathologically by biopsies before treatment. The diagnostic rate was significantly higher in polypoid (76.47%) and submucosal lesions (68.75%), than in ulcerative lesions (12.00%). However, biopsies were only taken in 56.31% patients, including 51.52% of polypoid lesions, 35.56% of submucosal lesions and 100.00% of ulcerative lesions. Endoscopic resection removed 61.76% of GI-NENs, including six by CBP, 14 by snare polypectomy with electrocauterization, 28 by endoscopic mucosal resection (EMR) and 15 by endoscopic submucosal dissection (ESD). 51.52% polypoid GI-NENs had infiltrated the submucosa under microscopic examination. CBP had a significantly higher rate of remnant (33.33%) than snare polypectomy with electrocauterization, EMR and ESD (all 0.00%).

CONCLUSIONS

Biopsies for all polypoid and submucosal lesions will improve pre-operative diagnosis. The high rate of submucosal infiltration of polypoid GI-NENs determined that CBP was inadequate in the treatment of GI-NENs. Diminutive polypoid GI-NENs that disappeared after CBP had a high risk of remnant and should be closely followed up over the long term.

Large cell neuroendocrine carcinoma of the rectum presenting with extensive metastatic disease

Introduction. Rectal large cell neuroendocrine carcinoma (LCNEC) is a poorly differentiated neoplasm that is very rare and belongs within the poorest prognostic subgroup among primary colorectal neoplasms. Here, we describe a case of LCNEC of the rectum, which highlights the aggressive clinical course and poor prognosis associated with this disease. Case Presentation. We report a case of a 63-year-old male who presented to our hospital with a one-month history of lower abdominal pain, constipation, and weight loss. A computed tomography (CT) scan of the chest, abdomen, and pelvis revealed a rectal mass as well as metastatic disease of the liver and lung. Flexible sigmoidoscopy revealed a fungating, ulcerated and partially obstructing rectal mass located 6 cm from the anal verge. This mass was biopsied and pathological examination of the resected specimen revealed features consistent with a large cell neuroendocrine carcinoma. Conclusion. Rectal large cell neuroendocrine carcinomas are rare and have a significantly worse prognosis than adenocarcinomas. At diagnosis, a higher stage and metastatic disease are likely to be found. It is important to differentiate large cell, poorly differentiated neuroendocrine carcinomas from adenocarcinomas of the colon and rectum pathologically because patients may benefit from alternative cytotoxic chemotherapeutic regimens.

Long-term outcome of patients with locally resected high- and low-risk rectal carcinoid tumors

BACKGROUND

Tumor size and lymphovascular invasion are known high-risk factors for lymph node and distant metastasis in patients with rectal carcinoid tumors. However, the optimal treatment for these tumors remains controversial.

AIM

The aim of this paper is to compare the outcome of local or radical resection between patients with high-risk (tumor size >10 mm or lymphovascular invasion) disease and those with low-risk (tumor size ≤10 mm, no lymphovascular invasion) disease.

METHODS

Patients with rectal carcinoid tumors treated between January 1990 and March 2010 were identified retrospectively and classified into low- and high-risk groups.

RESULTS

In total, 83 patients with rectal carcinoid tumors were included, 53 (64%) of whom were identified as low-risk and 30 (36%) as high-risk. Local resection was performed in 50 (60%) low-risk and 24 (29%) high-risk patients, and postoperative recurrence was observed in one (1%) of the high-risk patients who underwent local resection and one (11%) who underwent radical resection. No recurrence was observed in the low-risk group. Kaplan-Meier analysis of the patients who underwent local resection revealed that the 10-year disease-free survival rate was 100% in the low-risk group and 83.3% in the high-risk group.

CONCLUSIONS

There was no significant difference in outcome between local and radical resection.

Classification, clinicopathologic features and treatment of gastric neuroendocrine tumors

Gastric neuroendocrine tumors (GNETs) are rare lesions characterized by hypergastrinemia that arise from enterochromaffin-like cells of the stomach. GNETs consist of a heterogeneous group of neoplasms comprising tumor types of varying pathogenesis, histomorphologic characteristics, and biological behavior. A classification system has been proposed that distinguishes four types of GNETs; the clinicopathological features of the tumor, its prognosis, and the patient’s survival strictly depend on this classification. Thus, correct management of patients with GNETs can only be proposed when the tumor has been classified by an accurate pathological and clinical evaluation of the patient. Recently developed cancer therapies such as inhibition of angiogenesis or molecular targeting of growth factor receptors have been used to treat GNETs, but the only definitive therapy is the complete resection of the tumor. Here we review the literature on GNETs, and summarize the classification, clinicopathological features (especially prognosis), clinical presentations and current practice of management of GNETs. We also present the latest findings on new gene markers for GNETs, and discuss the effective drugs developed for the diagnosis, prognosis and treatment of GNETs.

Clinically detected gastroenteropancreatic neuroendocrine tumors are on the rise: Epidemiological changes in Germany

AIM: To study the epidemiologic changes of gastroenteropancreatic neuroendocrine tumors (GEP-NET) in Germany, we analyzed two time periods 1976-1988 and 1998-2006.

METHODS: We evaluated epidemiological data of GEP-NET from the former East German National Cancer Registry (DDR Krebsregister, 1976-1988) and its successor, the Joint Cancer Registry (GKR, 1998-2006), which was founded after German reunification. Due to a particularly substantial database the epidemiological data from the federal states of Mecklenburg-Western Pomerania, Saxony, Brandenburg and Thuringia, covering a population of more than 10.8 million people, were analyzed. Survival probabilities were calculated using life table analysis. In addition, GEP-NET patients were evaluated for one or more second (non-GEP-NET) primary malignancies.

RESULTS: A total of 2821 GEP neuroendocrine neoplasms were identified in the two registries. The overall incidence increased significantly between 1976 and 2006 from 0.31 (per 100.000 inhabitants per year) to 2.27 for men and from 0.57 to 2.38 for women. In the later period studied (2004-2006), the small intestine was the most common site. Neuroendocrine (NE) neoplasms of the small intestine showed the largest absolute increase in incidence, while rectal NE neoplasms exhibited the greatest relative increase. Only the incidence of appendiceal NET in women showed little change between 1976 and 2006. Overall survival of patients varied for sex, tumor site and the two periods studied but improved significantly over time. Interestingly, about 20% of the GEP-NET patients developed one or more second malignancies. Their most common location was the gastrointestinal tract. GEP-NET patients without second malignancies fared better than those with one or more of them.

CONCLUSION: The number of detected GEP-NET increased about 5-fold in Germany between 1976 and 2006. At the same time, their anatomic distribution changed, and the survival of GEP-NET patients improved significantly. Second malignancies are common and influence the overall survival of GEP-NET patients. Thus, GEP-NET warrant our attention as well as intensive research on their tumorigenesis.

Endoscopic treatment for early foregut neuroendocrine tumors

Foregut neuroendocrine tumors (NETs) include those arising in the esophagus, stomach, pancreas, and duodenum and seem to have a broad range of clinical behavior from benign to metastatic. Several factors including the advent of screening endoscopy may be related to increased incidence of gastrointestinal NETs; thus, many foregut NETs are diagnosed at an early stage. Early foregut NETs, such as those of the stomach and duodenum, can be managed with endoscopic treatment because of a low frequency of lymph node and distant metastases. However, controversy continues concerning the optimal management of early foregut NETs due to a lack of controlled prospective studies. Several issues such as indications, technical issues, and outcomes of endoscopic treatment for early foregut NETs are reviewed based on some published studies.

Unexpected endoscopic full-thickness resection of a duodenal neuroendocrine tumor

A 57-year-old man underwent endoscopy for investigation of a duodenal polyp. Endoscopy revealed a hemispheric submucosal tumor, about 5 mm in diameter, in the anterior wall of the duodenal bulb. Endoscopic biopsy disclosed a neuroendocrine tumor histologically, therefore endoscopic mucosal resection was conducted. The tumor was effectively and evenly elevated after injection of a mixture of 0.2% hyaluronic acid and glycerol at a ratio of 1:1 into the submucosal layer. A small amount of indigo-carmine dye was also added for coloration of injection fluid. The lesion was completely resected en bloc with a snare after submucosal fluid injection. Immediately, muscle-fiber-like tissues were identified in the marginal area of the resected defect above the blue-colored layer, which suggested perforation. The defect was completely closed with a total of 9 endoclips, and no symptoms associated with peritonitis appeared thereafter. Histologically, the horizontal and vertical margins of the resected specimen were free of tumor and muscularis propria was also seen in the resected specimen. Generally, endoscopic mucosal resection is considered to be theoretically successful if the mucosal defect is colored blue. The blue layer in this case, however, had been created by unplanned injection into the subserosal rather than the submucosal layer.

Duodenal somatostatinoma: a case report and review of the literature

Introduction

About 70% of well-differentiated endocrine tumors arise from the gastrointestinal tract. Duodenal well-differentiated endocrine tumors account for only 2.6% of all neuroendocrine tumors. Following the first two case reports of somatostatin-secreting tumors in 1977, fewer than 200 cases of somatostatinoma have been reported. These tumors of the duodenum are usually silent and asymptomatic, but can cause gastrointestinal symptoms. Depending on the localization of the tumor, multiple surgical procedures can be performed, ranging from local resection to pancreaticoduodenectomy.

Case presentation

Here, we report a case of a submucosal duodenal mass in a 42-year-old Turkish White man presenting with nausea, vomiting, fatigue and abdominal pain. The treatment decision of pancreaticoduodenectomy made preoperatively was later altered to intraoperative removal via local resection with sphincteroplasty.

Conclusion

Tumors of the periampullary region are considered highly malignant, and the Whipple operation is usually the only procedural treatment. In the current case, we decided not to perform pancreaticoduodenectomy but to excise the mass intraoperatively, and consequently avoided unnecessary resection of the pancreas and anastomosis to undilated hepatic and pancreatic ducts. This protective strategy prevented duodenum- and pancreas-related morbidity.