Resection of pancreatic neuroendocrine tumors: defining patterns and time course of recurrence

Enucleation for Sporadic Nonfunctioning Pancreatic Neuroendocrine Tumors Larger than 2 Centimeters Is Associated with Equivalent Morbidity and Survival Compared to Smaller Tumors: A Multi-Institutional Study

INTRODUCTION

Nonfunctioning pancreatic neuroendocrine tumor (NF-PanNET) ≤2 cm can be observed or resected. Surgery remains recommended for NF-PanNET >2 cm but its extent, enucleation (EN) versus formal resection, remains controversial.

METHODS

Multicentric retrospective cohort of sporadic NF-PanNET patients treated with EN. Short- and long-term outcomes were compared according to tumor size on imaging ≤2 cm versus >2 cm.

RESULTS

131 patients underwent EN for NF-PanNET, including 103 (79.0%) ≤2 cm and 28 (21.0%) >2 cm (extremes, 4-55 mm). Patients' characteristics were comparable, and tumor characteristics only differed in their diameter. Clavien III-IV complications were similar (18.4% vs. 17.9%, p = 1.00) with one death in NF-PanNET ≤2 cm. Grade B/C pancreatic fistula were comparable (16.5% vs. 10.7%, p = 0.850). In NF-PanNET >2 cm there were more pT2/3 stage tumors (85.7% vs. 21.4%, p < 0.001), similar rates of grade G2/3 tumors (25% vs. 16.5%, p = 0.408) with a median Ki67 of 2 (interquartile range: 1-3), and of lymphovascular and perineural invasions. Lymph node picking was done in 46 (35.1%) patients, with a higher median number of harvested lymph nodes in NF-PanNET >2 cm (4 vs. 3, p = 0.01). All were pN0. R0 resection rate (78.6% vs. 82.5%, respectively; p = 0.670) was equivalent. Five-year overall (100% vs. 99%, p = 0.602) and 10-year disease-free (96% vs. 92%, respectively; p = 0.532) survivals were comparable.

CONCLUSIONS

EN for selected NF-PanNET >2 cm carries equivalent morbidity, overall and disease-free survivals compared to those observed with NF-PanNET ≤2 cm.

Critical appraisal of the adequacy of surgical indications for non-functioning pancreatic neuroendocrine tumours

BACKGROUND

The lack of preoperative prognostic factors to accurately predict tumour aggressiveness in non-functioning pancreatic neuroendocrine tumours may result in inappropriate management decisions. This study aimed to critically evaluate the adequacy of surgical treatment in patients with resectable non-functioning pancreatic neuroendocrine tumours and investigate preoperative features of surgical appropriateness.

METHODS

A retrospective study was conducted on patients who underwent curative surgery for non-functioning pancreatic neuroendocrine tumours at San Raffaele Hospital (2002-2022). The appropriateness of surgical treatment was categorized as appropriate, potential overtreatment and potential undertreatment based on histologic features of aggressiveness and disease relapse within 1 year from surgery (early relapse).

RESULTS

A total of 384 patients were included. Among them, 230 (60%) received appropriate surgical treatment, whereas the remaining 154 (40%) underwent potentially inadequate treatment: 129 (34%) experienced potential overtreatment and 25 (6%) received potential undertreatment. The appropriateness of surgical treatment was significantly associated with radiological tumour size (P < 0.001), tumour site (P = 0.012), surgical technique (P < 0.001) and year of surgical resection (P < 0.001). Surgery performed before 2015 (OR 2.580, 95% c.i. 1.570 to 4.242; P < 0.001), radiological tumour diameter < 25.5 mm (OR 6.566, 95% c.i. 4.010 to 10.751; P < 0.001) and pancreatic body/tail localization (OR 1.908, 95% c.i. 1.119 to 3.253; P = 0.018) were identified as independent predictors of potential overtreatment. Radiological tumour size was the only independent determinant of potential undertreatment (OR 0.291, 95% c.i. 0.107 to 0.791; P = 0.016). Patients subjected to potential undertreatment exhibited significantly poorer disease-free survival (P < 0.001), overall survival (P < 0.001) and disease-specific survival (P < 0.001).

CONCLUSIONS

Potential overtreatment occurs in nearly one-third of patients undergoing surgery for non-functioning pancreatic neuroendocrine tumours. Tumour diameter emerges as the sole variable capable of predicting the risk of both potential surgical overtreatment and undertreatment.

Consensus on the clinical diagnosis and treatment of grade 3 pancreatic neuroendocrine tumors

The World Health Organization (WHO) 2017 classifications for neuroendocrine neoplasms (NENs) subdivided grade 3 pancreatic neuroendocrine neoplasms (pNENs) into G3 well-differentiated pancreatic neuroendocrine tumors (G3 pNETs) and poorly differentiated pancreatic neuroendocrine carcinomas (pNECs), according to the mitotic count, Ki-67 index, and cell differentiation. As a new category, G3 pNETs remain a challenging group of tumors to manage by lacking large randomized trials and consensus to support its clinical practice. Therefore, the Chinese Pancreatic Surgery Association, Chinese Society of Surgery, Chinese Medical Association gathered experts in this field to formulate this consensus for the diagnosis and treatment of G3 pNETs.

Pancreatic neuroendocrine tumors: Are tumors smaller than 2 cm truly indolent?

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are relatively rare but rank as the second most common pancreatic neoplasm. They can be functional, causing early metabolic disturbances due to hormone secretion, or non-functional and diagnosed later based on tumor size-related symptoms. Recent diagnoses of PNETs under 2 cm in size have sparked debates about their management; some practitioners advocate for surgical removal and others suggest observation due to the tumors' lower potential for malignancy. However, it is unclear whether managing these small tumors expectantly is truly safe.

AIM

To evaluate poor prognostic factors in PNETs based on tumor size (> 2 cm or < 2 cm) in surgically treated patients.

METHODS

This cohort study included 64 patients with PNETs who underwent surgical resection between 2006 and 2019 at a high-complexity reference hospital in Medellín, Colombia. To assess patient survival, quarterly follow-ups were conducted during the first year after surgery, followed by semi-annual consultations at the hospital's hepatobiliary surgery department. Qualitative variables were described using absolute and relative frequencies, and quantitative variables were expressed using measures of central tendency and their corresponding measures of dispersion.

RESULTS

The presence of lymph node involvement, neural involvement, and lymphovascular invasion were all associated with an increased risk of mortality, with hazard ratios of 5.68 (95%CI: 1.26-25.61, P = 0.024), 6.44 (95%CI: 1.43-28.93, P = 0.015), and 24.87 (95%CI: 2.98-207.19, P = 0.003), respectively. Neural involvement and lymphovascular invasion were present in tumors smaller than 2 cm in diameter and those larger than 2 cm in diameter. The recurrence rates between the two tumor groups were furthermore similar: 18.2% for tumors smaller than 2 cm and 21.4% for tumors larger than 2 cm. Patient survival was additionally comparable between the two tumor groups.

CONCLUSION

Tumor size does not dictate prognosis; lymph node and lymphovascular involvement affect mortality, which highlights that histopathological factors-rather than tumor size-may play a role in management.

Predicting resection margin status of pancreatic neuroendocrine tumors on CT: performance of NCCN resectability criteria

OBJECTIVE

To test the performance of the National Comprehensive Cancer Network (NCCN) CT resectability criteria for predicting the surgical margin status of pancreatic neuroendocrine tumor (PNET) and to identify factors associated with margin-positive resection.

METHODS

Eighty patients with pre-operative CT and upfront surgery were retrospectively enrolled. Two radiologists assessed the CT resectability (resectable [R], borderline resectable [BR], unresectable [UR]) of the PNET according to NCCN criteria. Logistic regression was used to identify factors associated with resection margin status. κ statistics were used to evaluate interreader agreements. Kaplan-Meier method with log-rank test was used to estimate and compare recurrence-free survival (RFS).

RESULTS

Forty-five patients (56.2%) received R0 resection and 35 (43.8%) received R1 or R2 resection. R0 resection rates were 63.6-64.2%, 20.0-33.3%, and 0% for R, BR, and UR diseases, respectively (all p ≤ 0.002), with a good interreader agreement (κ, 0.74). Tumor size (<2 cm, 2-4 cm, and >4 cm; odds ratio (OR), 9.042-18.110; all p ≤ 0.007) and NCCN BR/UR diseases (OR, 5.918; p = 0.032) were predictors for R1 or R2 resection. The R0 resection rate was 91.7% for R disease <2 cm and decreased for larger R disease. R0 resection and smaller tumor size in R disease improved RFS.

CONCLUSION

NCCN resectability criteria can stratify patients with PNET into distinct groups of R0 resectability. Adding tumor size to R disease substantially improves the prediction of R0 resection, especially for PNETs <2 cm.

ADVANCES IN KNOWLEDGE

Tumor size and radiologic resectability independently predicted margin status of PNETs.

Recurring Pancreatic Neuroendocrine Tumor: Timing and Pattern of Recurrence and Current Treatment

OBJECTIVE

The objective of this study was to describe the pattern of recurrence, treatments received, as well the oncological outcomes, of pancreatic neuroendocrine tumors (PanNETs) following curative surgery.

BACKGROUND

PanNETs recur in 10% to 15% of cases following surgery. Information on the natural history and management of recurring disease is lacking.

MATERIALS AND METHODS

Patients with PanNET that underwent curative surgery at 4 institutions between 2000 and 2019 were identified. Patients with poorly differentiated tumors, unknown tumor grade and differentiation, hereditary syndromes, unknown margin or R2 status, metastatic, and those that had neoadjuvant treatment or perioperative mortality were excluded. Clinical variables were assessed including first site of recurrence, treatment received, and survival outcomes.

RESULTS

A total of 1402 patients were included: 957 (74%) had grade 1, 322 (25%) had grade 2, and 13 (1%) had grade 3 tumors. Median follow-up was 4.8 years (interquartile range: 2-8.2 years). Cumulative incidence of recurrence at 5 years was 13% (95% CI: 11%-15.2%) for distant disease, 1.4% (95% CI: 0.8%-2.3%) for locoregional recurrence, and 0.8% (95% CI: 0.4%-1.5%) for abdominal nodal recurrence. Patients who recurred had 2.89 increased risk of death (95% CI: 2-4.1) as compared with patients who did not recur. Therapy postrecurrence included: somatostatin analogs in 111 (61.0%), targeted therapies in 48 (26.4%), liver-directed therapies in 61 (33.5%), peptide receptor radionuclide therapy in 30 (16.5%), and surgery in 46 (25.3%) patients. Multiple treatments were used in 103 (57%) cases. After the first recurrence, 5-year overall survival was 74.6% (95% CI: 67.4%-82.5%).

CONCLUSIONS

Recurrence following surgery is infrequent but reduces survival. Most recurrences are distant and managed with multiple therapies. Prospective studies are needed to establish strategies for surveillance and the sequence of treatment to control the disease and prolong survival.

Low Prognostic Nutritional Index Is Common and Associated with Poor Outcomes following Curative-Intent Resection for Gastro-Entero-Pancreatic Neuroendocrine Tumors

INTRODUCTION

To investigate the impact of prognostic nutritional index (PNI) on short- and long-term outcomes of patients who underwent curative-intent resection for gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs).

METHODS

Patients with GET-NETs who underwent curative-intent resection were identified from a multi-center database. The prognostic impact of clinicopathological factors including PNI on post-operative outcomes were evaluated. A novel nomogram was developed and externally validated.

RESULTS

A total of 2,099 patients with GEP-NETs were included in the training cohort; 255 patients were in the external validation cohort. Median PNI (n = 973) was 47.4 (IQR 43.1-52.4). At the time of presentation, 1,299 (61.9%) patients presented with some type of clinical symptom. Low-PNI (≤42.2) was associated with gastrointestinal symptoms, as well as nodal metastasis and distant metastasis (all p < 0.05). Patients with a low PNI had a higher incidence of severe (≥Clavien-Dindo grade IIIa: low PNI 24.9% vs. high PNI 15.4%, p = 0.001) and multiple (≥3 types of complications: low PNI 14.5% vs. high PNI 9.2%, p = 0.024) complications, as well as a worse overall survival (OS)(5-year OS, low PNI 73.7% vs. high PNI 88.5%, p < 0.001), and RFS (5-year RFS, low PNI 68.5% vs. high PNI 79.8%, p = 0.008) versus patients with high PNI (>42.2). A nomogram based on PNI, tumor grade and metastatic disease demonstrated excellent discrimination and calibration to predict OS in both the training (C-index 0.748) and two external validation (C-index 0.827, 0.745) cohorts.

CONCLUSIONS

Low PNI was common and associated with worse short- and long-term outcomes among patients with GEP-NETs.

Diagnostic Accuracy of ki-67 Labeling Index in Endoscopic Ultrasonography-Fine-Needle Aspiration Cytology and Biopsy of Pancreatic Neuroendocrine Neoplasms

BACKGROUND

This study aimed to compare the diagnostic accuracy of the Ki-67 labeling index (LI) between endoscopic ultrasonography-fine-needle aspiration cytology/biopsy (EUS-FNAC/FNB) and surgical specimens of pancreatic neuroendocrine neoplasms (PanNENs).

METHODS

Conventional meta-analysis and diagnostic test accuracy (DTA) reviews were performed on 17 eligible studies. The DTA review involved calculating the sensitivity, specificity, diagnostic odds ratio (OR), and area under the curve (AUC) of the summary receiver operating characteristic (SROC) curve. In addition, subgroup analysis was conducted based on EUS-FNAC and FNB, tumor grade, and tumor size.

RESULTS

The overall concordance rate of WHO grade based on Ki-67 LI between the EUS-FNAC/FNB and the surgical specimen was 0.767 (95% confidence interval (CI), 0.713-0.814). Concordance rates of the EUS-FNAC and EUS-FNB subgroups were 0.741 (95% CI, 0.681-0.794) and 0.839 (95% CI, 0.738-0.906), respectively. In the DTA review for grade 3, the sensitivity and specificity were calculated to be 0.786 (95% CI, 0.590-0.917) and 0.998 (95% CI, 0.987-1.000), respectively. The diagnostic OR and AUC of the SROC curve were 150.220 (95% CI, 46.145-489.000) and 0.983, respectively. The sensitivity and specificity were observed to be highest in the grade 1 and 3 subgroups, respectively.

CONCLUSIONS

Higher concordance of tumor grade based on Ki-67 LI was observed between EUS-FNAC/FNB and surgical specimens, indicating the potential usefulness of Ki-67 LI in predicting PanNEN tumor grade in EUS-FNAC/FNB.

Sigmoid colon schwannoma difficult to distinguish from peritoneal dissemination 13 years after pancreatic neuroendocrine tumor surgery

BACKGROUND

Schwannoma, which clinicians sometimes struggle to diagnose, is a tumor arising from Schwann cells of peripheral nerves, often in the soft tissues and rarely in the gastrointestinal tract. Pancreatic neuroendocrine tumor (PNET) is rare among pancreatic tumors, and recurrence can occur long after resection. Here, we were presented with a case where a sigmoid colon schwannoma was difficult to distinguish from a postoperative recurrence of PNET and was diagnosed after laparoscopic resection.

CASE PRESENTATION

A 51-year-old man was diagnosed with PNET (NET G2) after a distal pancreatectomy (DP) 13 years ago. The patient underwent hepatectomy due to liver metastasis 12 years after initial radical surgery. The follow-up magnetic resonance imaging (MRI) after hepatectomy showed pelvic nodules, and laparoscopic surgery was performed for both diagnosis and treatment because peritoneal dissemination of PNET could not be ruled out. Since the tumor was in the sigmoid colon, a partial colon resection was performed. The histopathological diagnosis was a schwannoma, and the patient was discharged on the seventh postoperative day.

CONCLUSIONS

We experienced a case of sigmoid colon schwannoma that was difficult to differentiate from peritoneal dissemination of PNET and was later diagnosed after laparoscopic resection. In addition, this case involved a long-term postoperative recurrence of PNET that was amenable to radical resection, further establishing the importance of long-term imaging follow-up.

Machine learning-based model for prediction and feature analysis of recurrence in pancreatic neuroendocrine tumors G1/G2

BACKGROUND

Pancreatic neuroendocrine neoplasms (PanNENs) are a heterogeneous group of tumors. Although the prognosis of resected PanNENs is generally considered to be good, a relatively high recurrence rate has been reported. Given the scarcity of large-scale reports about PanNEN recurrence due to their rarity, we aimed to identify the predictors for recurrence in patients with resected PanNENs to improve prognosis.

METHODS

We established a multicenter database of 573 patients with PanNENs, who underwent resection between January 1987 and July 2020 at 22 Japanese centers, mainly in the Kyushu region. We evaluated the clinical characteristics of 371 patients with localized non-functioning pancreatic neuroendocrine tumors (G1/G2). We also constructed a machine learning-based prediction model to analyze the important features to determine recurrence.

RESULTS

Fifty-two patients experienced recurrence (14.0%) during the follow-up period, with the median time of recurrence being 33.7 months. The random survival forest (RSF) model showed better predictive performance than the Cox proportional hazards regression model in terms of the Harrell's C-index (0.841 vs. 0.820). The Ki-67 index, residual tumor, WHO grade, tumor size, and lymph node metastasis were the top five predictors in the RSF model; tumor size above 20 mm was the watershed with increased recurrence probability, whereas the 5-year disease-free survival rate decreased linearly as the Ki-67 index increased.

CONCLUSIONS

Our study revealed the characteristics of resected PanNENs in real-world clinical practice. Machine learning techniques can be powerful analytical tools that provide new insights into the relationship between the Ki-67 index or tumor size and recurrence.

The Surgical and Therapeutic Activities of Non-Functional Pancreatic Neuroendocrine Tumors at a High-Volume Institution

BACKGROUND

This study aimed to summarize the surgical and therapeutic activities of non-functional pancreatic neuroendocrine tumors (NF-PanNETs) and perform survival analyses of a 15-year single-institutional cohort of NF-PanNETs.

METHODS

In total, 1001 patients with neuroendocrine neoplasms treated at Fudan University Shanghai Cancer Center were screened for inclusion, and 509 patients with NF-PanNETs from 2006 to 2020 were included. For time trend analyses, the 15-year study period was randomly divided into three periods. Survival analyses used the Kaplan-Meier method and Cox regression models.

RESULTS

The total number of resected NF-PanNETs increased over the 15-year study period, from 5 resections in 2006 to 94 resections in 2020. A significant decrease in the tumor size was observed, from a mean of 4.0 cm to 3.3 cm, and to 3.0 cm in the most recent period (p = 0.006). Minimally invasive techniques gradually increased from 3.5% to 12.9%, and finally to 46.4% in the most recent period (p < 0.001). In non-metastatic and resected tumors, the tumor size (p < 0.001), positive lymph node (p < 0.001), adjuvant treatment (p = 0.048), and tumor grade (p < 0.001) were independent prognostic factors for recurrence-free survival (RFS). The microvascular invasion (p = 0.024) and tumor grade (p = 0.013) were independent prognostic factors for overall survival (OS). A malignant transformation from NET into neuroendocrine carcinoma was observed.

CONCLUSIONS

An increasing number of NF-PanNETs resection and minimally invasive surgery was shown. In non-metastatic and resected tumors NF-PanNETs, tumor size, positive lymph node, adjuvant treatment, and tumor grade were independent predictors of RFS. Microvascular invasion and tumor grade were independent prognostic factors for OS.

Recurrence and outcomes of non-functional pancreatic neuroendocrine tumours post-resection: an Australian retrospective, multicentre cohort study

INTRODUCTION

Pancreatic neuroendocrine tumours (PNETs) are heterogenous entities with variable clinical outlook. The prevalence of PNETs is increasing in Australia. Despite this, data on peri-operative management and post-operative prognosis for Australian patients is scant in the literature.

METHODS

Patients from two tertiary hospitals in Victoria were recruited. Inclusion criteria included patients who underwent curative surgical resection for primary, non-functioning, PNETs without metastases from January 2011 to December 2021. Patients were identified via histopathological reports, CMBS and ICD-10 codes. Data were sourced from Electronic Medical Records, outpatient notes and letters.

RESULTS

Sixty-three patients (34 Male, 29 Female) underwent surgical resection for PNETs. Fifty-three patients (84.1%) had a post-operative complication, and 21 (33.3%) had severe complications. Two patients had disease recurrence. Head PNETs had higher Ki-67% (5.33 vs. 2.72, P = 0.29), and likelihood of nodal spread (9 (36%) vs. 4 (16%), P = 0.054). Pancreatic Head resections were also associated with more frequent ICU admissions (21 (84%) vs. 18 (54.5), P = 0.024), longer ICU stays (4.05 vs. 2.17 days, P = 0.10) and hospital stays (26.76 vs. 8.27 days, P = <0.001).

CONCLUSION

Within the limitations of this study, it demonstrates that surgical resection of PNET carries a significant morbidity with a low rate of recurrence. Additionally, Pancreatic head NETs may be associated with higher grades and increased likelihood of nodal metastases. Considering this, careful patient selection is paramount.

Predicting Novel Drug Candidates for Pancreatic Neuroendocrine Tumors via Gene Signature Comparison and Connectivity Mapping

INTRODUCTION

There is a paucity of effective treatment options for advanced pancreatic neuroendocrine tumors (pNETs). Genome-wide analyses may allow for potential drugs to be identified based on differentially expressed genes (DEGs).

METHODS

Oligo microarray data of RNA expression profiling of pNETs and normal pancreas tissues were downloaded from the Gene Expression Omnibus. Functional and pathway enrichment information of the DEGs was obtained using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases. Corresponding homologous proteins were analyzed and potential therapeutic drugs for pNETs were identified using the Connectivity Map and Drug-Gene Interaction Database.

RESULTS

Assessment of raw data from 12,610 pNET genes demonstrated that 1082 and 380 genes were upregulated and downregulated, respectively, compared with normal pancreas tissue. Upregulated pathways were associated with nitrogen metabolism (i.e., GABAergic synapse, and graft-versus-host disease), whereas downregulated pathways included C-type leptin receptor signaling pathway, pertussis and AMPK signaling pathway. In particular, the protein-protein interaction analysis revealed 10 upregulated hub genes (DYNLL1, GNB5, GNB2, GNG4, GNAI2, GNAI1, HIST2H2BE, NUP107, NUP133, and SNAP25) and 10 downregulated hub genes (CXCL8, F2, CXCL2, GCG, SST, INS, GALR3, CCL20, ADRA2B, and CXCL6). Using the Drug-Gene Interaction Database, candidate drugs for pNETs treatment included 3 EGFR inhibitors (canertinib, erlotinib, WZ-4-145), as well as other cell-signaling pathway inhibitors such as AG-592, acarbose, lonidamine, azacytidine, rottlerin, and HU-211.

CONCLUSION

Using available genetic atlas data, potential drug candidates for treatment of pNETs were identified based on differentially expressed genes. These results may help focus efforts on identifying targeted agents with therapeutic efficacy to treat patients with pNETs.

Identifying Risk Factors and Patterns for Early Recurrence of Pancreatic Neuroendocrine Tumors: A Multi-Institutional Study

Simple Summary

Approximately 30% of patients with a pancreatic neuroendocrine tumor (pNET) will develop metastases. Curative-intent treatment largely involves resection. Identifying patients with early recurrence (ER) following resection might help tailor adjuvant therapies and the surveillance intensity. The aim of this retrospective study was to determine an evidence-based cut-off value for ER, and to explore risk factors associated with ER. ER was identified 18 months after surgery. Tumor size (OR 1.20, 95% CI 1.05–1.37, p = 0.007) and positive lymph nodes (OR 4.69, 95%CI 1.41–15.58, p = 0.01) were independently associated with ER. Patients with ER had lower post-recurrence free survival and overall survival than patients with late recurrence. These data support intensive follow-up shortly after surgery, and adjuvant therapy may help improve survival in pNET patients with ER after surgery.

Abstract

Background: Identifying patients at risk for early recurrence (ER) following resection for pancreatic neuroendocrine tumors (pNETs) might help to tailor adjuvant therapies and surveillance intensity in the post-operative setting. Methods: Patients undergoing surgical resection for pNETs between 1998–2018 were identified using a multi-institutional database. Using a minimum p-value approach, optimal cut-off value of recurrence-free survival (RFS) was determined based on the difference in post-recurrence survival (PRS). Risk factors for early recurrence were identified. Results: Among 807 patients who underwent curative-intent resection for pNETs, the optimal length of RFS to define ER was identified at 18 months (lowest p-value of 0.019). Median RFS was 11.0 months (95% 8.5–12.60) among ER patients (n = 49) versus 41.0 months (95% CI: 35.0–45.9) among non-ER patients (n = 77). Median PRS was worse among ER patients compared with non-ER patients (42.6 months vs. 81.5 months, p = 0.04). On multivariable analysis, tumor size (OR: 1.20, 95% CI: 1.05–1.37, p = 0.007) and positive lymph nodes (OR: 4.69, 95% CI: 1.41–15.58, p = 0.01) were independently associated with ER. Conclusion: An evidence-based cut-off value for ER after surgery for pNET was defined at 18 months. These data emphasized the importance of close follow-up in the first two years after surgery.

Clinical relevance of performing endoscopic ultrasound-guided fine-needle biopsy for pancreatic neuroendocrine tumors less than 2 cm

BACKGROUND

We sought to define the diagnostic yield and concordance rates between endoscopic ultrasound (EUS)-fine-needle aspiration (FNA) and surgical pathology specimen following resection of pancreatic neuroendocrine tumors (pNET) less than 2 cm.

METHODS

Patients with a pNET less than 2 cm who underwent EUS-FNA were identified using a multi-institutional international database. Tumor differentiation, and Ki-67 index, as determined through EUS-FNA were examined and concordance rates between EUS-FNA and the surgical pathology were assessed.

RESULTS

Among 628 patients with a pNET less than 2 cm, 57.2% of patients had an EUS-FNA performed. Patients who underwent EUS had slightly smaller size tumors (1.3 vs 1.4 cm), and the pNETs were less likely to be functional (15.3% vs 26.8%) or symptomatic (48.5% vs 56.5%) (both P < .05). Among 314 patients with a pNET less than 2 cm who had an EUS-FNA performed at the time of diagnosis, 243 (73.2%) had the diagnosis confirmed by preoperative EUS-FNA. Tumor differentiation and Ki-67 could be determined by EUS-FNA in only 26.4% and 20.1% of patients, respectively. Concordance rate between EUS-FNA and pathology was high relative to tumor differentiation (92.7%) and Ki-67 (81.0%).

CONCLUSION

Tumor differentiation and Ki-67 index could be determined by EUS-FNA in only 26.4% and 20.1% of cases, respectively. Further studies should focus on EUS techniques to optimize diagnostic yield and cell extraction in the preoperative setting.

Clinical and Molecular Risk Factors for Recurrence Following Radical Surgery of Well-Differentiated Pancreatic Neuroendocrine Tumors

Well-differentiated pancreatic neuroendocrine tumors are increasingly diagnosed neoplasms. For localized disease, surgery is the first-line therapy and is curative in most cases. However, although recurrence is a rare event, it can still occur up to 10 years from surgery, worsening the prognosis. Many clinical and pathological factors have been associated with recurrence; however, it is currently unclear how to accurately discern patients at risk for relapse of disease from those that should be considered cured. In this review, we focus on clinical, pathological, and molecular factors associated with recurrence and discuss available prediction tools to assess the risk of recurrence following surgery.

Surgical management of primary pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are the second most common malignancy of the pancreas, and their incidence is increasing. PanNETs are a diverse group of diseases which range from benign to malignant, can be sporadic or associated with genetic mutations, and be functional or nonfunctional. In as much, the treatment and management of PanNETs can vary from a "Wait and See" approach to orthotopic liver transplantation (OLT). Despite this, surgical resection is still the primary treatment modality to achieve cure. This review focuses on the surgical management of PanNETs.

Surgical outcomes of patients with duodenal vs pancreatic neuroendocrine tumors following pancreatoduodenectomy

BACKGROUND

To investigate the short- and long-term outcomes of patients undergoing pancreaticoduodenectomy (PD) for duodenal neuroendocrine tumors (dNETs) vs pancreatic neuroendocrine tumors (pNETs).

METHOD

Patients undergoing PD for dNETs or pNETs between 1997 and 2016 were identified from a multi-institutional database. Overall survival (OS) and recurrence-free survival (RFS) were evaluated.

RESULTS

Among 276 patients who underwent PD, 244 (88.4%) patients had a primary pNET, whereas 32 (11.6%) patients had a dNET. Following PD, postoperative morbidity and mortality were comparable. While the total number of lymph nodes examined was similar between the two groups (median, dNETs 15.0 vs pNETs 13.0; P= .648), patients with dNETs had a higher incidence of lymph node metastasis (LNM) (60.0% vs 38.2%; P = .022) and a larger number of metastatic nodes (median, 3.5 vs 2.0; P = .039). No differences in OS or RFS were noted among patients with dNETs vs pNETs in both unadjusted and adjusted analyses. Among patients who recurred after PD, patients with dNETs were more likely to recur early (within 2 years, 100% vs 49.2%; P = .029) and at an extrahepatic site (intrahepatic-only recurrence, 20.0% vs 54.1%; P = 0.142) vs patients with pNETs.

CONCLUSIONS

Patients with dNETs and pNETs had a similar prognosis following PD. Data on differences in the incidence of LNM, as well as in recurrence time and patterns may help to inform the treatment of these patients.

Prognostic and predictive factors on overall survival and surgical outcomes in pancreatic neuroendocrine tumors: recent advances and controversies

Introduction: Recent advances in diagnostic modalities and therapeutic agents have raised the importance of prognostic factors in predicting overall survival, as well as predictive factors for surgical outcomes, in tailoring therapeutic strategies of patients with pancreatic neuroendocrine neoplasms (panNENs).Areas covered: Numerous recent studies of panNEN patients report the prognostic values of a number of clinically related factors (clinical, laboratory, imaging, treatment-related factors), pathological factors (histological, classification, grading) and molecular factors on long-term survival. In addition, an increasing number of studies showed the usefulness of various factors, specifically biomarkers and molecular makers, in predicting recurrence and mortality related to surgical treatment. Recent findings (from the last 3 years) in each of these areas, as well as recent controversies, are reviewed.Expert commentary: The clinical importance of prognostic and predictive factors for panNENs is markedly increased for both overall outcome and post resection, as a result of recent advances in all aspects of the diagnosis, management and treatment of panNENs. Despite the proven prognostic utility of routinely used tumor grading/classification and staging systems, further studies are required to establish these novel prognostic factors to support their routine clinical use.

Follow-Up Recommendations after Curative Resection of Well-Differentiated Neuroendocrine Tumours: Review of Current Evidence and Clinical Practice

The incidence of neuroendocrine neoplasms (NENs) is increasing, especially for patients with early stages and grade 1 tumours. Current evidence also shows increased prevalence, probably reflecting earlier stage diagnosis and improvement of treatment options. Definition of adequate postsurgical follow-up for NENs is a current challenge. There are limited guidelines, and heterogeneity in adherence to those available is notable. Unfortunately, the population of patients at greatest risk of recurrence has not been defined clearly. Some studies support that for patients with pancreatic neuroendocrine tumours (PanNETs), factors such as primary tumour (T), stage, grade (Ki-67), tumour size, and lymph node metastases (N) are of relevance. For bronchial neuroendocrine tumours (LungNETs) and small intestinal neuroendocrine tumours (siNETs), similar factors have been identified. This review summarises the evidence supporting the rationale behind follow-up after curative resection in well-differentiated PanNETs, siNETs, and LungNETS. Published evidence informing relapse rate, disease-free survival, and relapse patterns are discussed, together with an overview of current guidelines informing postsurgical investigations and duration of follow-up.