Are there prognostic factors related to recurrence in pancreatic endocrine tumors?

Oncogenic pathway signatures predict the risk of progression and recurrence in well-differentiated pancreatic neuroendocrine tumors

BACKGROUND

Pancreatic neuroendocrine tumors (pNETs) are genomically diverse tumors. The management of newly diagnosed well-differentiated pNETs is limited by a lack of sensitivity of existing biomarkers for prognostication. Our goal was to investigate the potential utility of genetic markers as a predictor of progression-free survival (PFS) and recurrence-free survival (RFS).

METHODS

Whole-exome sequencing of resected well-differentiated, low and intermediate-grade (G1 and G2) pNETs and normal adjacent tissue from patients who underwent resection from 2005 to 2015 was performed. Genetic alterations were classified using pan-genomic and oncogenic pathway classifications. Additional samples with genetic and clinicopathologic data available were obtained from the publicly available International Cancer Genome Consortium (ICGC) database and included in the analysis. The prognostic relevance of these genomic signatures on PFS and RFS was analyzed.

RESULTS

Thirty-one patients who underwent resection for pNET were identified. Genomic analysis of mutational, copy number, cytogenetic, and complex phenomena revealed similar patterns to prior studies of pNETs with relatively few somatic gene mutations but numerous instances of copy number changes. Analysis of genomic and clinicopathologic outcomes using the combined data from our study as well as the ICGC pNET cohort (n = 124 patients) revealed that the recurrent pattern of whole chromosome loss (RPCL) and metastatic disease were independently associated with disease progression. When evaluating patients with local disease at the time of resection, RPCL and alterations in the TGFβ oncogenic pathway were independently associated with the risk of recurrence.

CONCLUSIONS

Well-differentiated pNETs are genomically diverse tumors. Pathway signatures may be prognostic for predicting disease progression and recurrence.

Prognostic factors for relapse in resected gastroenteropancreatic neuroendocrine neoplasms: A systematic review and meta-analysis

BACKGROUND

Gastroenteropancreatic neoplasms (GEP-NENs)can potentially be cured through surgical resection, but only 42-57% achieve 5-year disease-free survival.There is a lack of consensus regarding the factorsassociated withrelapse followingresection ofGEP-NENs.

METHODS

Asystematic review identified studies reporting factors associated with relapse in patients with GEP-NENs following resection of a primary tumour. Meta-analysis was performed to identify the factors prognostic for relapse-free survival (RFS)oroverall survival (OS).

RESULTS

63 studies comprising 13,715 patients were included; 56 studies reported on pancreatic NENs (12,418 patients), 24 reported on patients with grade 1-2 tumours (4,735 patients). Median follow-up was 44.2 months, median RFS was 32 months. Pooling of multivariable analyses of GEP-NENs (all sites and grades) found the following factors predicted worse RFS (all p values < 0.05): vascular resection performed, metastatic disease resected, grade 2 disease, grade 3 disease, tumour size > 20 mm, R1 resection, microvascular invasion, perineural invasion, Ki-67 > 5% and any lymph node positivity. In a subgroup of studies comprising exclusively of grade 1-2 GEP-NENs, R1 resection, perineural invasion, grade 2 disease, any lymph node positivity and tumour size > 20 mm predicted worse RFS (all p values < 0.05). Few OSdata were available for pooling; in univariableanalysis(entire cohort), grade 2 predicted worse OS (p = 0.007), whileR1 resectiondid not (p = 0.14).

CONCLUSIONS

The factors prognostic for worse RFS following resection of a GEP-NEN identified in this meta-analysis could be included in post-curative treatment surveillance clinical guidelines and inform the stratification and inclusion criteria of future adjuvant trials.

Pancreatic Neuroendocrine Neoplasms: Does Sex Matter?

Genetic and molecular disparities between men and women have a role in the differing incidence, pathophysiology, clinical signs, and treatment outcome of several cancers. Sex differences in cancer incidence are attributed to regulation at the genetic/molecular level and to sex hormones that in turn modulate gene expression in various cancers. Sex differences in the incidence of cancer, its aggressiveness, and the disease prognosis have been reported for several types of cancer but little is known for pancreatic neuroendocrine neoplasms (PNENs). The aim of this Opinion article is to provide an overview of sex differences in PNENs in terms of epidemiology, pathophysiology, treatment responses, prognosis, and survival. This overview might allow better tailoring of the management of PNENs.

Systematic Review and Metaanalysis of Lymph Node Metastases of Resected Pancreatic Neuroendocrine Tumors

BACKGROUND

The optimal surgical strategy for pancreatic neuroendocrine tumors (PNETs) is unknown. However, current guidelines recommend a watch-and-wait strategy for small nonfunctional PNETs (NF-PNETs). The aim of this study is to investigate the risk stratification and prognostic significance of lymph node metastasis (LNM) of PNETs to guide decision-making for lymphadenectomy.

PATIENTS AND METHODS

The MEDLINE and Web of Science databases were systematically searched for studies reporting either risk factors of LNM in resected PNETs or survival of patients with LNM. The weighted average incidence of LNM was calculated according to tumor characteristics. Random-effects metaanalyses were performed, and pooled hazard ratios (HR) and their 95% confidence intervals (CI) were calculated to determine the impact of LNM on overall survival (OS). In subgroup analyses, NF-PNETs were assessed.

RESULTS

From a total of 5883 articles, 98 retrospective studies with 13,374 patients undergoing resection for PNET were included. In all PNETs, the weighted median rates of LNM were 11.5% for small (≤ 2 cm) PNETs and 15.8% for G1 PNETs. In NF-PNETs, the rates were 11.2% for small PNETs and 10.3% for G1 PNETs. LNM of all PNETs (HR 3.87, 95% CI 3.00-4.99, P < 0.001) and NF-PNETs (HR 4.98, 95% CI 2.81-8.83, P < 0.001) was associated with worse OS.

CONCLUSIONS

LNM is potentially prevalent even in small and well-differentiated PNETs and is associated with worse prognosis. A watch-and-wait strategy for small NF-PNETs should be reappraised, and oncologic resection with lymphadenectomy can be considered. Prospective and controlled studies are needed in the future.

Predictors of Recurrence and Survival in Patients With Surgically Resected Pancreatic Neuroendocrine Tumors

OBJECTIVE

Given the lack of consensus on surveillance guidelines after pancreatic neuroendocrine tumor (PanNET) resection, we assessed outcomes in a large cohort of patients with nonmetastatic, surgically resected PanNETs.

METHODS

Data of patients with PanNETs resected between 1990 and 2017 were retrospectively collected using databases at 3 academic institutions. The National Death Index was queried to determine vital status. Kaplan-Meier analysis was used to estimate recurrence-free survival (RFS) and disease-specific survival (DSS) rates. Variables associated with recurrence and disease-related death were identified through Cox multivariate analyses.

RESULTS

Of 307 patients with PanNET who underwent resection, recurrence occurred in 79 (26%) of patients. For stage I and II disease, 5-year RFS rates were 90% and 43%, whereas 5-year DSS rates were 98% and 86% (P < 0.0001 and P = 0.0038, respectively). For grades 1, 2, and 3 disease, 5-year RFS rates were 87%, 49%, and 18%, and 5-year DSS rates were 98%, 89%, and 51% (P < 0.0001 for both). Stage II, grade 2, and grade 3 disease were each associated with increased recurrence and disease-specific death.

CONCLUSIONS

Stage and grade are important prognostic factors that should be utilized to tailor postsurgical surveillance after curative resection of PanNET.

Novel scoring system for recurrence risk classification of surgically resected G1/2 pancreatic neuroendocrine tumors - Retrospective cohort study

BACKGROUND

Existing staging systems for pancreatic neuroendocrine neoplasms only provide accuracy in stratifying disease severity without enough sensitivity in prognosis predicting. Previously presented models mainly set overall survival as endpoint but ignore the importance of recurrence.

METHODS

Univariate and multivariate analyses were retrospectively conducted on the potential prognostic factors of 245 patients who underwent curable surgery of G1/2 pancreatic neuroendocrine tumors from December 2002 to May 2018 in our institute. Proposed model based on statistically significant factors were tested for recurrence risk classification estimation validity as measured by discrimination (receiver operator characteristic [ROC] curve and Harrell's c-index [HCI]) and calibration.

RESULTS

Multivariate analyses found lymph node metastasis, larger tumor size and grade 2 independent risk factors of disease-free survival (DFS). The novel scoring system for recurrence risk classification sorted patients into three groups: score<15.4 for low risk (79.0%, 3- and 5-year recurrence risk 0.8% and 4.3%, median DFS not reached), score>15.4, <24.5 for intermediate risk (20.8%, 3- and 5-year recurrence risk 11.6% and 21.4%, median DFS 70 months) and score >24.5 for high risk (10.2%, 3- and 5-year recurrence risk 37.3% and 68.7%, median DFS 49 months).The area under curve (AUC) and HCI of our system were 0.871 and 0.929, superior to those of European Neuroendocrine Tumor Society (AUC 0.833, HCI 0.806).

CONCLUSION

The presented system can be utilized to identify G1/2 pancreatic neuroendocrine tumors patients with high recurrence risk, which might be appropriate for peri-operative adjuvant therapy.

A rational approach to postoperative surveillance for resected non-functional pancreatic neuro-endocrine tumours

BACKGROUND

Non-functional pancreatic neuroendocrine tumours (NF-PNETs) are rare and have highly variable outcomes. Current guidelines recommend surveillance for NF-PNETs <2 cm. Patients who ultimately have surgical resection are at risk of disease recurrence, and data to support postoperative surveillance protocols are lacking. The aims of this study were to i) identify post-operative predictors of recurrence and ii) risk stratify patients at risk of recurrence.

METHODS

Consecutive patients who underwent surgery for NF-PNETs between 2002 and 2015 were identified retrospectively. Data were collected on demographics, pre-operative laboratory results and histopathological tumour characteristics. Statistical analyses were based on penalised Cox-regression modelling and a decision-tree model. Comparison of the variables identified was performed using ROC curves to identify the most sensitive and specific variable associated with disease recurrence.

RESULTS

We identified 73 patients (38 males) with a median age of 61.5 years (range: 31-79). The median period of follow-up was 49 months (5-131). During follow up, 10 deaths (13.9%) were recorded and disease recurrence occurred in 12 patients (16.4%). The Kaplan-Meier predicted 1-,3- and 5-year recurrence-free survival rates were 98.6% (95% CI = 95.9, 100%), 85.4% (76.9-94.8%) and 72% (58.7-88.2%) respectively. Cox multivariate analysis identified poor tumour differentiation (WHO G3 grade) and lymph node ratio (LNR) as independent predictors for recurrence (p < 0.05). A simple criterion of 'tumour grade G3 or LNR ≥0.1' was found to be sensitive and specific in detecting disease recurrence.

CONCLUSION

Our results have identified a simple and sensitive criterion for risk stratifying post-resection surveillance. Prospective validation in larger patient cohort is now warranted.

Time-trend and recurrence analysis of pancreatic neuroendocrine tumors

This study aimed to evaluate the evolving trends in clinicopathological features of pancreatic neuroendocrine tumors and to analyze the predictors of recurrence after curative resection. Data collected retrospectively from a single center between January 1990 and December 2017 were analyzed. Patients were categorized chronologically into three groups for evolving time-trend analysis. Overall, 542 patients (300 female, 55.4%) underwent surgical resection for pancreatic neuroendocrine tumors, including 435 (80.3%) with non-functional tumors. Time-trend analysis revealed that the surgically resected pancreatic neuroendocrine tumor number increased consistently; however, the incidental non-functional pancreatic neuroendocrine tumor number also increased over time (P < 0.001). The 5- and 10-year disease-free survival rates were 86.4 and 81.3%, respectively. The overall recurrence rate was 13.7%, and the most common site of recurrence was the liver. The median time to recurrence after primary surgery was 19.0 (range 0.8-236.3) months, and the median survival time after recurrence was 22.6 (range 0.4-126.9) months. On multivariate analysis, grade G3 pancreatic neuroendocrine tumors (hazard ratio 4.51; P < 0.001), lymph node metastasis (hazard ratio 2.46; P = 0.009), lymphovascular invasion (hazard ratio 3.62; P = 0.004), perineural invasion (hazard ratio 2.61; P = 0.004) and resection margin (hazard ratio 4.20; P = 0.003) were independent prognostic factors of disease-free survival. The surgically resected pancreatic neuroendocrine tumor number increased over time mainly because of an increase in incidentally discovered non-functional pancreatic neuroendocrine tumors. Grade G3 pancreatic neuroendocrine tumors, lymph node metastasis, lymphovascular invasion, perineural invasion and a positive resection margin were significant predictors of worse disease-free survival in patients with surgically resected pancreatic neuroendocrine tumors.

Neoplasms of the Neuroendocrine Pancreas: An Update in the Classification, Definition, and Molecular Genetic Advances

This review focuses on discussing the main modifications of the recently published 2017 WHO Classification of Neoplasms of the Neuroendocrine Pancreas (panNEN). Recent updates separate pancreatic neuroendocrine tumors into 2 broad categories: well-differentiated pancreatic neuroendocrine tumors (panNET) and poorly differentiated pancreatic neuroendocrine carcinoma (panNEC), and incorporates a new subcategory of "well-differentiated high-grade NET (G3)" to the well-differentiated NET category. This new classification algorithm aims to improve the prediction of clinical outcomes and survival and help clinicians select better therapeutic strategies for patient care and management. In addition, these neuroendocrine neoplasms are capable of producing large quantity of hormones leading to clinical hormone hypersecretion syndromes. These functioning tumors include, insulinomas, glucagonomas, somatostatinomas, gastrinomas, VIPomas, serotonin-producing tumors, and ACTH-producing tumors. Although most panNENs arise as sporadic diseases, a subset of these heterogeneous tumors present as parts on inherited genetic syndromes, such as multiple endocrine neoplasia type 1, von Hippel-Lindau, neurofibromatosis type 1, tuberous sclerosis, and glucagon cell hyperplasia and neoplasia syndromes. Characteristic clinical and morphologic findings for certain functioning and syndromic panNENs should alert both pathologists and clinicians as appropriate patient management and possible genetic counseling may be necessary.

MRI-based nomogram estimates the risk of recurrence of primary nonmetastatic pancreatic neuroendocrine tumors after curative resection

BACKGROUND

Accurate estimation of the recurrence of pancreatic neuroendocrine tumors help with prognosis, guide follow-up, and avoid futile treatments.

PURPOSE

To investigate whether MRI features could preoperatively estimate the recurrence of pancreatic neuroendocrine tumors (PNETs) and to refine a novel prognostic model through developing a nomogram incorporating various MRI features.

STUDY TYPE

Retrospective.

POPULATION

In all, 81 patients with clinicopathologically confirmed nonmetastatic PNETs.

FIELD STRENGTH/SEQUENCES

1.5 T MR, including T₁ -weighted, T₂ -weighted, and diffusion-weighted imaging sequences.

ASSESSMENT

Qualitative and quantitative MRI features of PNET were assessed by three experienced radiologists.

STATISTICAL TESTS

Uni- and multivariable analyses for recurrence-free survival (RFS) were evaluated using a Cox proportional hazards model. The MRI-based nomogram was then designed based on multivariable logistic analysis in our study and the performance of the nomogram was validated according to C-index, calibration, and decision curve analyses.

RESULTS

MRI features, including tumor size (hazard ratio [HR]: 14.131; P = 0.034), enhancement pattern (HR: 21.821, P = 0.032), and the apparent diffusion coefficient (ADC) values (HR: 0.055, P = 0.038) were significant independent predictors of RFS at multivariable analysis. The performance of the nomogram incorporating various MRI features (with a C-index of 0.910) was improved compared with that based on tumor size, enhancement pattern, and ADC alone (with C-index values of 0.672, 0.851, and 0.809, respectively). The calibration curve of the nomogram exhibited perfect consistency between estimation and observation at 0.5, 1, and 2 years after surgery. The decision curve showed that a nomogram incorporating three features had more favorable clinical predictive usefulness than any single feature.

DATA CONCLUSION

MRI features can be considered effective recurrence predictors for PNETs after surgery. The preliminary nomogram incorporating various MRI features could assess the risk of recurrence in PNETs and may be used to optimize individual treatment strategies.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:397-409.

Pancreatic neuroendocrine tumors in MEN1 disease: a mono-centric longitudinal and prognostic study

PURPOSE

Multiple endocrine neoplasia type 1 (MEN1) is an inherited endocrine neoplastic syndrome associated with a greater risk of endocrine tumor development like pancreatic neuroendocrine tumors (p-NET), with different clinical characteristics from sporadic ones. This paper aims to compare clinical, hystological and morphological aspects of p-NET in patients affected from MEN1 (MEN1+) and not-affected ones (MEN1-).

METHODS

We performed a retrospective observational study. Data was collected between December 2010 and December 2015, including patients with a histological diagnosis of p-NET and radiological imaging. We compared clinical, histological, radiological, and prognostic aspects of MEN+ p-NET with MEN-1 p-NET.

RESULTS

Of the 45 patients enrolled, 13 MEN1+ and 21 MEN1- cases were analyzed. Frequency of not secreting p-NETs and insulin secreting p-NETs, histopathological grades and Ki67 expression were superimposable between MEN1+ and MEN1- patients. MEN1+ pNETs are more often multicentric compared to MEN1- pNETs. Frequency of liver and nodes metastatic spread was higher in MEN1- p-NET compared to MEN1+ p-NET. Analyzing p-NET according to the disease outcome, we found that recovered and stable p-NETs in MEN1+ patients, compared to MEN1- cases, are diagnosed at lower age (p = 0.04/p = 0.002) and that are more frequently multifocal lesions (p = 0.009/p = 0.002).

CONCLUSIONS

In our study pNETs in MEN1+ and pNETs in MEN1- don't significantly differ for prognosis but only for clinical features. p-NET stage disease and prognosis can be positively influenced by early diagnosis and screening in index patients' first-degree relatives.

Is radical surgery always curative in pancreatic neuroendocrine tumors? A cure model survival analysis

BACKGROUND

Adjuvant therapy after curative surgery for sporadic pancreatic neuroendocrine tumor (pNETs) is not currently recommended, assuming that all patients could be cured by a radical resection. The aim of our study is to establish how many and which kind of patients remained uncured after radical resection of pNET.

METHODS

Retrospective study involving 143 resected sporadic pNETs. The survival analysis was carried out using the cure model, describing the cure fraction and the excess of risk recurrence. Multivariate analyses were made in order to evaluate the non negligible effect of demographics, clinical and pathological factors on survival parameters. The results were reported as percentages, fractions, ORs and HRs with 95% confidence interval (95 CI %).

RESULTS

The cure fraction and the excess of hazard rate of the whole population were 57.1% (37.4-74.6, 95% CI) and 0.06 (0.03-0.07, 95% CI), respectively. Two independent factors were related to the cure fraction: TNM stage (OR 0.27 ± 0.17; P = 0.002) and grading (OR 0.11 ± 0.18; P = 0.004). Considering the excess of hazard rate, only two independent factors were related to an increased risk of recurrence: TNM stage (HR 3.49 ± 1.12; P = 0.004) and grading (HR 4.93 ± 1.82; P < 0.001).

CONCLUSION

The radical surgery has a high probability of cure in stages I-II or in grading 1 while, in stages III-IV or in grading 3 tumors, surgery alone failed to achieve a "cure". A multimodal treatment should be employed in order to avoid a recurrence of the disease.

Clinical, pathological, and demographic factors associated with development of recurrences after surgical resection in elderly patients with neuroendocrine tumors

Background

Incidence of locoregional neuroendocrine tumors (NETs) is rising. However, after curative resection, the patterns and risk factors associated with recurrence remain unknown. Consensus guidelines recommend surveillance every 6-12 months for up to 10 years after surgery for resected, well-differentiated NETs irrespective of patient demographics, site, grade or stage of tumor with few exceptions.

Patients and methods

From the Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we identified localized and regional stage NET patients who underwent surgical resection between January 2002 and December 2011. Development of recurrence was identified by capturing at least two claims indicative of metastatic disease until 31 December 2013.

Results

Of the 2366 identified patients (median age 73 years), 369 (16%) developed metastatic disease within 5 years and only an additional 1% developed metastases between years 5 and 10 with the majority dying due to unrelated causes. The 5-year risk of developing metastases (hazard ratio, HR) varied significantly (log-rank P < 0.001) by grade: 9.9% versus 25.9% (2.2) versus 48.1% (4.4) for grades 1, 2, and  ≥ 3, respectively; stage: 10.3% versus 31.1% (2.8) for localized versus regional; primary tumor size: 7.6% versus 15% (1.3) versus 26.6% (1.5) for <1, 1-2, and > 2 cm, respectively; and site: ranging from 11.3% for colon to 23.9% for pancreas.

Conclusions

Contrary to current guidelines, our study suggests that surveillance recommendations should be tailored according to patient and tumor characteristics. Surveillance past 5 years may be avoided in elderly patients with competing morbidities or low risk of recurrence. Pancreatic, lung, higher grade, and regional NETs have a higher risk of recurrence and may be considered for future adjuvant trials.

Comparison of Recurrence Between Pancreatic and Duodenal Neuroendocrine Neoplasms After Curative Resection: A Single-Institution Analysis

BACKGROUND

The primary site of a neuroendocrine neoplasms (NEN) around the head of the pancreas is sometimes difficult to assess before resection, and the characteristics of the primary site around this region have not been elucidated for recurrence after curative resection. In this study, the clinicopathologic characteristics of pancreatic NEN (PanNEN) and duodenal NEN (DuNEN) were evaluated, and the risk factors as well as the recurrence types after resection were investigated.

METHODS

Consecutively diagnosed NEN patients at the authors' hospital from January 2000 to July 2016 were evaluated in this study. For 117 PanNEN patients and 31 non-ampullary DuNEN patients, R0 resection was achieved. The median follow-up period was 8.1 years.

RESULTS

In this study, 27 PanNEN patients (23.1%) had recurrences, with a median disease-free survival (DFS) of 133 months, whereas 11 DuNEN patients (35.5%) had recurrences, with a median DFS of 156 months. The PanNEN patients tended to have primary recurrence in the liver (85.2%), followed by lymph nodes (11.1%). The independent risk factors for short DFS were lymph node metastasis at resection (p = 0.001) and microvascular invasion (p = 0.048). In contrast, the DuNEN patients were likely to have lymph node metastasis (81.8%). The independent risk factors for short DFS were lymph node metastasis at resection (p = 0.003) and large diameter (p = 0.013).

CONCLUSIONS

Most initial recurrences of PanNEN occurred in the liver, whereas those of DuNEN appeared in lymph nodes, suggesting that proper diagnosis of the primary site and appropriate imaging methods for surveillance after resection are necessary.

Pancreatic neuroendocrine tumor: Correlations between MRI features, tumor biology, and clinical outcome after surgery

PURPOSE

To assess which magnetic resonance imaging (MRI) features are associated with pNETs (pancreatic neuroendocrine tumors) grade based on the WHO classification, as well as identify MRI features related to disease progression after surgery.

MATERIALS AND METHODS

In this Institutional Review Board (IRB)-approved study, 1.5T and 3.0T MRI scans of 80 patients with surgically verified pNETs were assessed. The images were evaluated for tumor location; size; pattern; predominant signal intensity on precontrast T₁ - and T₂ -weighted images, as well as on postcontrast arterial and portal venous phase T₁ -weighted sequences; presence of pancreatic duct dilatation; pancreatic atrophy; restricted diffusion; vascular involvement by the tumor; extrapancreatic tumor spread; and synchronous liver metastases. Tumors were graded based on the WHO classification and patients were followed-up with computed tomography (CT) or MRI after surgical resection. Data were analyzed with Student's t and chi-square tests, logistic regression, and Kaplan-Meier curves.

RESULTS

The MRI features that were associated with aggressive tumors were: size >2.0 cm (odds ratio [OR] = 4.8, P = 0.002), "T₂ nonbright lesions" on T₂ -weighted images (OR = 4.6, P = 0.008), presence of pancreatic ductal dilatation (OR = 4.9, P = 0.024), and restricted diffusion within the lesion (OR = 4.9, P = 0.013). Differences in progression-free survival distribution were found for patients whose pNETs were associated with the following MRI features: size >2.0 cm (χ² (1) = 6.0, P = 0.014), "nonbright lesions" on T₂ -weighted images (χ² (1) = 6.8, P = 0.009), and presence of pancreatic duct dilatation (χ² (1) = 10.9, P = 0.001).

CONCLUSION

MRI features can be used to assess pNETs aggressiveness and identify patients at risk for early disease progression after surgical resection.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:425-432.

Prognostic factors of long-term outcome in surgically resectable pancreatic neuroendocrine tumors: A 12-year experience from a single center

The present study was performed to assess the prognostic factors with respect to patient survival and clinicopathological characteristics for patients who underwent surgery for pancreatic neuroendocrine tumors (PNETs). A retrospective review of patients pathologically diagnosed with PNETs at the First Affiliated Hospital, Zhejiang University School of Medicine (Hangzhou, Zhejiang, China) between September 2002 and September 2013 was conducted. The clinicopathological findings, overall survival (OS) rate and disease-free survival (DFS) rate of the patients with PNETs were analyzed. Prognostic factors were determined by univariate and multivariate analyses. A total of 104 patients were selected. The median age at presentation was 52 years (range, 19–76 years). The most common surgical procedure was distal pancreatectomy (51.0%), followed by pancreaticoduodenectomy (27.9%) and local resection of the pancreas (16.3%). The majority of the tumors were of low or moderate grade (93.3%, grade 1 or 2) and were local or regional stage (92.3%). The 1-, 3- and 5-year OS rates were 95, 85 and 73%, respectively. Meanwhile, the 1-, 3- and 5-year DFS rates were 86, 72 and 68%, respectively. The OS and DFS rates were significantly different with regard to the grade (grades 1, 2 and 3; P<0.001) and stage (local, regional and distant disease; P<0.001). Furthermore, patients with a low Ki-67 index experienced superior OS and DFS rates compared with patients with a high Ki-67 index (P<0.001). The presence of lymph node metastasis was predictive of inferior OS and DFS rates compared with the absence of lymph node metastasis (P<0.001). OS rate for PNETs was significantly affected by resection margin status (P<0.001). In multivariable analysis, the significant factors associated with OS rate were stage (P=0.02), grade (P<0.001), lymph node status (P=0.025), Ki-67 index (P=0.031) and resection margin status (P<0.001). Meanwhile, stage (P=0.001), grade (P=0.017), lymph node status (P=0.02) and Ki-67 index (P=0.016) were prognostic factors for DFS rate. In conclusion, grade, stage, Ki-67 index and lymph node involvement are significant prognostic factors for OS and DFS rates in surgically resectable PNETs. Furthermore, surgical margin status may also be an independent predictor for the prognosis of PNETs. It is anticipated that these findings may provide useful predictors of clinical survival, particularly in the setting of resected disease.

Prognostic factors for disease relapse in patients with neuroendocrine tumours who underwent curative surgery

AIM

Surgery is the only modality of cure in patients diagnosed with neuroendocrine tumours (NETs). The aim of this study was to identify prognostic factors associated with disease relapse in patients with NETs treated by potentially-curative surgery.

METHODS

Sequential patients registered in The Christie European NET Society (ENETS) Centre of Excellence, with grade (G)1 or G2 NETs who had undergone curative surgery (February 2002-June 2014) were included. Investigated prognostic factors for relapse were: age, gender, TNM stage, tumour-localisation, functionality, genetic predisposition, presence of multiple NETs, second malignancy, grade (Ki-67-based), presence of vascular and/or perineural invasion, necrosis, surgical margin (R0/R1), Eastern Cooperative Oncology Group performance status and Adult Comorbidity Evaluation co-morbidity score.

RESULTS

One hundred and eighty-eight patients were identified [median age of 60 years (range 16-89)]. With a median follow-up of 2.6 years, 43 relapses occurred. The estimated median relapse-free survival (RFS) for the entire cohort was 8.0 years (95% confidence interval [CI] 5.9-10.0 years). In univariate analysis, primary NET location (p = 0.01), ENETS T-(HR-1.4; 95%-CI 1.0-2.0, p = 0.026), N-(HR-2.0, 95%-CI 1.1-3.9, p = 0.026) and M-stage (HR-2.6, 95%-CI 1.1-6.3, p = 0.052), grade (Ki-67%-based) (HR-2.5; 95%-CI 1.4-4.7; p = 0.003) and perineural invasion (HR-2.1; 95%-CI 1.1-3.9; p = 0.029) were prognostic for relapse. Factors remaining significant after multivariable analysis were tumour size (HR-1.67; 95%-CI 1.04-2.70; p = 0.03), nodal involvement (HR-2.61; 95%-CI 1.17-5.83; p = 0.013) and Ki-67 at the time of diagnosis (HR-1.93; 95%-CI 1.24-3.0; p = 0.002).

CONCLUSION

Size of tumour, lymph node involvement and Ki-67 were independent prognostic factors for relapse after potentially curative surgery in NET.

Postoperative Complications, In-Hospital Mortality and 5-Year Survival After Surgical Resection for Patients with a Pancreatic Neuroendocrine Tumor: A Systematic Review

Studies on postoperative complications and survival in patients with pancreatic neuroendocrine tumors (pNET) are sparse and randomized controlled trials are not available. We reviewed all studies on postoperative complications and survival after resection of pNET. A systematic search was performed in the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE from 2000-2013. Inclusion criteria were studies of resected pNET, which described postoperative complications separately for each surgical procedure and/or 5-year survival after resection. Prospective and retrospective studies were pooled separately and overall pooled if heterogeneity was below 75%. The random-effect model was used. Overall, 2643 studies were identified and after full-text analysis 62 studies were included. Pancreatic fistula (PF) rate of the prospective studies after tumor enucleation was 45%; PF-rates after distal pancreatectomy, pancreatoduodenectomy, or central pancreatectomy were, respectively, 14-14-58%. Delayed gastric emptying rates were, respectively, 5-5-18-16%. Postoperative hemorrhage rates were, respectively, 6-1-7-4%. In-hospital mortality rates were, respectively, 3-4-6-4%. The 5-year overall survival (OS) and disease-specific survival (DSS) of resected pNET without synchronous resected liver metastases were, respectively, 85-93%. Heterogeneity between included studies on 5-year OS in patients with synchronous resected liver metastases was too high to pool all studies. The 5-year DSS in patients with liver metastases was 80%. Morbidity after pancreatic resection for pNET was mainly caused by PF. Liver resection in patients with liver metastases seems to have a positive effect on DSS. To reduce heterogeneity, ISGPS criteria and uniform patient groups should be used in the analysis of postoperative outcome and survival.

The value of gadoxetic acid-enhanced and diffusion-weighted MRI for prediction of grading of pancreatic neuroendocrine tumors

BACKGROUND

Parenchyma-preserving resection for the treatment of benign pancreatic neuroendocrine tumors (NETs) has been tried, and preoperative prediction of benign pancreatic NET is important. Recently, diffusion-weighted imaging (DWI) of abdomen magnetic resonance imaging (MRI) has been used to characterize benign and malignant tumors and DWI might be helpful in prediction of benign pancreatic NETs.

PURPOSE

To evaluate the value of gadoxetic acid-enhanced MRI and DWI in predicting benign pancreatic NETs for determination of parenchyma-preserving resection.

MATERIAL AND METHODS

Our ethics committee approved this study with a waiver of informed consent given its retrospective design. We searched radiology and pathology databases from November 2010 to July 2012 to identify patients who underwent surgery for pancreatic NETs (<4 cm). Twenty patients in the benign group and 14 patients in the non-benign group were included in this study. Two radiologists analyzed the morphologic features, signal intensity on MR images including DWI (b = 800), and dynamic enhancement pattern of the tumors with consensus. The tumor-to-parenchyma ratio and tumor apparent diffusion coefficients (ADCs) were quantitatively assessed.

RESULTS

The benign pancreatic NETs were more often round (7/20, 35%) or ovoid (13/20, 65%) in shape and less hypovascular on the arterial phase (3/20, 15%) than were the non-benign pancreatic NETs (1/14, 7.1% and 5/14, 35.8%; 7/14, 50% respectively; P < 0.05). Main pancreatic duct dilatation by tumors was demonstrated only in non-benign pancreatic NETs (4/14, 28.4%; P = 0.021). ADC values and ratios were significantly different between benign pancreatic NETs (mean, 1.48 × 10(-3 )mm(2)/sec, 1.11 ± 0.25, each) and non-benign pancreatic NETs (mean, 1.04 × 10(-3 )mm(2)/sec, 0.74 ± 0.13, each) (P < 0.01). Other qualitative and quantitative analyses between benign and non-benign pancreatic NETs were not significantly different (P > 0.05).

CONCLUSION

Abdominal MRI with DWI may be useful for differentiating benign pancreatic NETs from non-benign pancreatic NETs, which might be helpful for determination of parenchyma-preserving resection.

The role of lymph node ratio in recurrence after curative surgery for pancreatic endocrine tumours

BACKGROUND

The prognostic role of lymph nodes metastasis in pancreatic neuroendocrine tumours is unclear.

METHODS

Retrospective study of 53 patients who underwent a curative standard resection for pancreatic neuroendocrine tumours. The endpoint was to define the role of the lymph nodes ratio in recurrence after curative surgery. The following data were considered as possible factors for predicting the risk of recurrence: gender, age, presence of symptoms, hormonal status, site of tumours, type of resection, size of the tumours, radical resection, pathological T, N and M stage, the Ki67 index, the number of lymph nodes harvested, the number of metastatic lymph nodes and the lymph node ratio. Recurrence rate and time of recurrence were evaluated.

RESULTS

Twelve (26.4%) patients developed a recurrence with a median time of 42.8 (1-305) months. At multivariate analysis, the only factors related to recurrence were: size of lesions (HR 1.1, C.I. 95% 1.0-1.1, P = 0.011), Ki67 ≥ 5% (HR 3.6, C.I. 95% 1.3-10, P = 0.014) and LNR > 0.07 (HR 5.2, C.I. 95% 1.1-25, P = 0.045).

CONCLUSIONS

Our study confirmed that the lymph nodes ratio played an important role in the recurrence rate and suggested that a low number of metastatic lymph nodes reduced the disease free survival.

Clinical presentation, recurrence, and survival in patients with neuroendocrine tumors: results from a prospective institutional database

The rarity of neuroendocrine tumors (NET) has contributed to a paucity of large epidemiologic studies of patients with this condition. We characterized presenting symptoms and clinical outcomes in a prospective database of over 900 patients with NET. We used data from patient questionnaires and the medical record to characterize presenting symptoms, disease-free survival (DFS), and overall survival (OS). The majority of patients in this database had gastroenteropancreatic NET. The median duration of patient-reported symptoms before diagnosis was 3.4 months; 19.5% reported durations from 1 to 5 years, 2.5% from 5 to 10 years, and 2% >10 years. The median DFS among patients with resected small bowel NET or pancreatic NET (panNET) was 5.8 and 4.1 years respectively. After correcting for left truncation bias, the median OS was 7.9 years for advanced small bowel NET and 3.9 years for advanced panNET. Chromogranin A (CGA) above twice the upper limit of normal was associated with shorter survival times (hazard ratios 2.8 (1.9, 4.0) P<0.001) in patients with metastatic disease, regardless of tumor subtype. Our data suggest that while most NET patients are diagnosed soon after symptom onset, prolonged symptom duration before diagnosis is a prominent feature of this disease. Though limited to observations from a large referral center, our observations confirm the prognostic value of CGA and suggest that median survival durations may be shorter than that reported in other institutional databases.

Surgical strategies for non-functioning pancreatic neuroendocrine tumours

BACKGROUND

The purpose of this study was to identify management strategies for non-functioning pancreatic neuroendocrine tumours (NF-PNETs) by analysis of surgical outcomes at a single institution.

METHODS

Archived records of patients with NF-PNETs who underwent surgery between 1994 and 2010 were reviewed.

RESULTS

Among 125 patients, the median tumour size was 2·5 (range 0·15-20·5) cm. Of the 51 NF-PNETs with a diameter of no more than 2 cm, 12 (24 per cent) were diagnosed as carcinoma. Overall 20 patients (16·0 per cent) had metastases to the lymph nodes. The minimum size of the tumour with lymph node metastasis was 1·2 cm. Having a NF-PNET of 2 cm or larger significantly increased the probability of a poorly differentiated carcinoma (P = 0·006), and having a NF-PNET of at least 2·5 cm significantly increased the probability of lymph node metastasis (P = 0·048). The 5-year cumulative survival rate after curative resection was 89·7 per cent. During a median follow-up of 31·5 months, there were 27 recurrences (23·1 per cent) and 13 disease-specific deaths (11·1 per cent) among the 117 patients who had an R0 resection. All patients who underwent repeat operations were alive without additional recurrence after a mean(s.d.) follow-up of 27·1(18·0) months.

CONCLUSION

Curative surgery should be performed for control of primary NF-PNETs. Lymph node dissection for NF-PNETs of 2·5 cm or larger and at least node sampling for tumours with a diameter of 1 cm or more are recommended. Debulking surgery should be considered for advanced tumours.

Lymph nodes and survival in pancreatic neuroendocrine tumors

HYPOTHESIS

Lymph node metastases decrease survival in patients with pancreatic neuroendocrine tumors (pNETs).

DESIGN

Prospective database searches.

SETTING

National Institutes of Health (NIH) and Stanford University Hospital (SUH).

PATIENTS

A total of 326 patients underwent surgical exploration for pNETs at the NIH (n = 216) and SUH (n = 110).

MAIN OUTCOME MEASURES

Overall survival, disease-related survival, and time to development of liver metastases.

RESULTS

Forty patients (12.3%) underwent enucleation and 305 (93.6%) underwent resection. Of the patients who underwent resection, 117 (35.9%) had partial pancreatectomy and 30 (9.2%) had a Whipple procedure. Forty-one patients also had liver resections, 21 had wedge resections, and 20 had lobectomies. Mean follow-up was 8.1 years (range, 0.3-28.6 years). The 10-year overall survival for patients with no metastases or lymph node metastases only was similar at 80%. As expected, patients with liver metastases had a significantly decreased 10-year survival of 30% (P < .001). The time to development of liver metastases was significantly reduced for patients with lymph node metastases alone compared with those with none (P < .001). For the NIH cohort with longer follow-up, disease-related survival was significantly different for those patients with no metastases, lymph node metastases alone, and liver metastases (P < .001). Extent of lymph node involvement in this subgroup showed that disease-related survival decreased as a function of the number of lymph nodes involved (P = .004).

CONCLUSIONS

As expected, liver metastases decrease survival of patients with pNETs. Patients with lymph node metastases alone have a shorter time to the development of liver metastases that is dependent on the number of lymph nodes involved. With sufficient long-term follow-up, lymph node metastases decrease disease-related survival. Careful evaluation of number and extent of lymph node involvement is warranted in all surgical procedures for pNETs.

Factors related to long-term survival in patients affected by well-differentiated endocrine tumors of the pancreas

Aim. To identify factors related to survival in patients affected by well-differentiated PETs (benign, uncertain behavior, and carcinoma) who underwent R0 pancreatic resection. Methods. Retrospective study of 74 consecutive patients followed up from January 1980 to December 2011. Prognostic factors were sex, age, type of tumor, presence of symptoms, type of surgical procedure, size of tumor, lymph nodes status, WHO classification, and TNM stage. Overall survival was evaluated using the Kaplan-Meier method. Cox regression analyses were used to identify the factors associated with prognosis in univariate and multivariate analysis. Results. The mean follow-up of all the patients was 106 ± 89 months. The 5-10-year long-term survival was 90.9% and 79.1%, respectively. At univariate analysis, patient age <55 years was significantly related to a better long-term survival compared to patients age ≥55 years (307 ± 15 months versus 192 ± 25 months; P = 0.010). Multivariate analysis showed that female gender (P = 0.006), patients without comorbidities (P = 0.033), and patients affected by well-differentiated benign pancreatic endocrine tumors (P = 0.008 and P = 0.002 in relation to tumors with uncertain behavior and carcinomas, resp.) were factors significantly related to a better long-term survival. Conclusions. Patients factors were strongly related to a better long-term survival in patients observed. WHO classification is a very useful prognostic tool for well-differentiated PETs.

Pancreatic neuroendocrine tumors with involved surgical margins: prognostic factors and the role of adjuvant radiotherapy

PURPOSE

Pancreatic neuroendocrine tumors (pNET) are rare neoplasms associated with poor outcomes without resection, and involved surgical margins are associated with a worse prognosis. The role of adjuvant radiotherapy (RT) in these patients has not been characterized.

METHODS AND MATERIALS

We retrospectively evaluated 46 consecutive patients with positive or close (<1 mm) margins after pNET resection, treated from 1983 to 2010, 16 of whom received adjuvant RT. Median RT dose was 50.4 Gy in 1.8-Gy fractions; half the patients received concurrent chemotherapy with 5-fluorouracil or capecitabine. No patients received adjuvant chemotherapy. Cox multivariate analysis (MVA) was used to analyze factors associated with overall survival (OS).

RESULTS

Median age at diagnosis was 56 years, and 52% of patients were female. Median tumor size was 38 mm, 57% of patients were node-positive, and 11% had a resected solitary liver metastasis. Patients who received RT were more likely to have larger tumors (median, 54 mm vs. 30 mm, respectively, p = 0.002) and node positivity (81% vs. 33%, respectively, p = 0.002) than those not receiving RT. Median follow-up was 39 months. Actuarial 5-year OS was 62% (95% confidence interval [CI], 41%-77%). In the group that did not receive RT, 3 patients (10%) experienced local recurrence (LR) and 5 patients (18%) developed new distant metastases, while in the RT group, 1 patient (6%) experienced LR and 5 patients (38%) developed distant metastases. Of all recurrences, 29% were LR. On MVA, male gender (adjusted hazard ratio [AHR] = 3.81; 95% CI, 1.21-11.92; p = 0.02) and increasing tumor size (AHR = 1.02; 95% CI, 1.01-1.04; p = 0.007) were associated with decreased OS.

CONCLUSIONS

Long-term survival is common among patients with involved-margin pNET. Despite significantly worse pathologic features among patients receiving adjuvant RT, rates of LR between groups were similar, suggesting that RT might aid local control, and merits further evaluation.

Surgical management of pancreatic neuroendocrine tumors

This study outlines the surgical management and clinicopathological findings of pancreatic neuroendocrine tumors (P-NETs). There are various surgical options, such as enucleation of the tumor, spleen-preserving distal pancreatectomy, distal pancreatectomy with splenectomy, pancreatoduodenectomy, and duodenum-preserving pancreas head resection. Lymph node dissection is performed for malignant cases. New guidelines and classifications have been proposed and are now being used in clinical practice. However, there are still no clear indications for organ-preserving pancreatic resection or lymph node dissection. Hepatectomy is the first choice for liver metastases of well-differentiated neuroendocrine carcinoma without extrahepatic metastases. On the other hand, cisplatin-based combination therapy is performed as first-line chemotherapy for metastatic poorly differentiated neuroendocrine carcinoma. Other treatment options are radiofrequency ablation, transarterial chemoembolization/embolization, and liver transplantation. Systematic chemotherapy and biotherapy, such as that with somatostatin analogue and interferon-α, are used for recurrence after surgery. The precise surgical techniques for enucleation of the tumor and spleen-preserving distal pancreatectomy are described.

Current surgical management of pancreatic endocrine tumor liver metastases

BACKGROUND

The management of metastatic disease in pancreatic endocrine tumors (PETs) demands a multidisciplinary approach and the cooperation of several medical specialties. The role of surgery is critical, even when a radical excision cannot always be achieved.

DATA SOURCES

A PubMed search of relevant articles published up to February 2011 was performed to identify current information about PET liver metastases regarding diagnosis and management, with an emphasis on surgery.

RESULTS

The early diagnosis of metastases and their accurate localization, most commonly in the liver, is very important. Surgical options include radical excision, and palliative excision to relieve symptoms in case of failure of medical treatment. The goal of the radical excision is to remove the primary tumor bulk and all liver metastases at the same time, but unfortunately it is not feasible in most cases. Palliative excisions include aggressive tumor debulking surgeries in well-differentiated carcinomas, trying to remove at least 90% of the tumor mass, combined with other additional destructive techniques such as hepatic artery embolization or chemoembolization to treat metastases or chemoembolization to relieve symptoms in cases of rapidly growing tumors. The combination of chemoembolization and systemic chemotherapy results in better response and survival rates. Other local destructive techniques include ethanol injection, cryotherapy and radiofrequency ablation.

CONCLUSION

It seems that the current management of PETs can achieve important improvements, even in advanced cases.

Suppression of uPAR retards radiation-induced invasion and migration mediated by integrin β1/FAK signaling in medulloblastoma

BACKGROUND

Despite effective radiotherapy for the initial stages of cancer, several studies have reported the recurrence of various cancers, including medulloblastoma. Here, we attempt to capitalize on the radiation-induced aggressive behavior of medulloblastoma cells by comparing the extracellular protease activity and the expression pattern of molecules, known to be involved in cell adhesion, migration and invasion, between non-irradiated and irradiated cells.

METHODOLOGY/PRINCIPAL FINDINGS

We identified an increase in invasion and migration of irradiated compared to non-irradiated medulloblastoma cells. RT-PCR analysis confirmed increased expression of uPA, uPAR, focal adhesion kinase (FAK), N-Cadherin and integrin subunits (e.g., α3, α5 and β1) in irradiated cells. Furthermore, we noticed a ∼2-fold increase in tyrosine phosphorylation of FAK in irradiated cells. Immunoprecipitation studies confirmed increased interaction of integrin β1 and FAK in irradiated cells. In addition, our results show that overexpression of uPAR in cancer cells can mimic radiation-induced activation of FAK signaling. Moreover, by inhibiting FAK phosphorylation, we were able to reduce the radiation-induced invasiveness of the cancer cells. In this vein, we studied the effect of siRNA-mediated knockdown of uPAR on cell migration and adhesion in irradiated and non-irradiated medulloblastoma cells. Downregulation of uPAR reduced the radiation-induced adhesion, migration and invasion of the irradiated cells, primarily by inhibiting phosphorylation of FAK, Paxillin and Rac-1/Cdc42. As observed from the immunoprecipitation studies, uPAR knockdown reduced interaction among the focal adhesion molecules, such as FAK, Paxillin and p130Cas, which are known to play key roles in cancer metastasis. Pretreatment with uPAR shRNA expressing construct reduced uPAR and phospho FAK expression levels in pre-established medulloblastoma in nude mice.

CONCLUSION/SIGNIFICANCE

Taken together, our results show that radiation enhances uPAR-mediated FAK signaling and by targeting uPAR we can inhibit radiation-activated cell adhesion and migration both in vitro and in vivo.