Clinicopathologic features and treatment trends of pancreatic neuroendocrine tumors: analysis of 9,821 patients

Contemporary Approaches to the Surgical Management of Pancreatic Neuroendocrine Tumors

The incidence of pancreatic neuroendocrine tumors (PNETs) is on the rise primarily due to the increasing use of cross-sectional imaging. Most of these incidentally detected lesions are non-functional PNETs with a small proportion of lesions being hormone-secreting, functional neoplasms. With recent advances in surgical approaches and systemic therapies, the management of PNETs have undergone a paradigm shift towards a more individualized approach. In this manuscript, we review the histologic classification and diagnostic approaches to both functional and non-functional PNETs. Additionally, we detail multidisciplinary approaches and surgical considerations tailored to the tumor's biology, location, and functionality based on recent evidence. We also discuss the complexities of metastatic disease, exploring liver-directed therapies and the evolving landscape of minimally invasive surgical techniques.

Portal vein resection in pancreatic neuroendocrine neoplasms

BACKGROUND

Surgery offers the only cure for borderline resectable or locally advanced pancreatic neuroendocrine neoplasms. Data on incidence, perioperative and long-term outcomes of portal vein resection for pancreatic neuroendocrine neoplasms are scarce. This study aimed to analyze the outcome and prognostic factors of portal vein resection in surgery for pancreatic neuroendocrine neoplasms.

METHODS

Consecutive patients were analyzed. Portal vein resection was classified according to the International Study Group of Pancreatic Surgery. Clinicopathologic features and overall and disease-free survival were assessed and compared with standard resection in a matched-pair analysis.

RESULTS

A total of 54 of 666 (8%) resected pancreatic neuroendocrine neoplasms patients underwent portal vein resection, including 7 (13%) tangential resections with venorrhaphy (type 1), 2 (4%) patch reconstructions (type 2), 35 (65%) end-to-end anastomoses (type 3), and 10 (19%) graft interpositions (type 4); 52% of those underwent pancreatoduodenectomy, 22% distal pancreatectomy, and 26% total pancreatectomy. Postoperative portal vein thrombosis occurred in 19%. Postoperative pancreatic fistula grades B and C (9% vs 16%; P = .357), complications Clavien-Dindo grade ≥IIIb (28% vs 13%; P = .071), and 90-day mortality rate (2% each) were not significantly different compared with 108 matched patients. The 5-year overall survival was 45% (standard resection: 68%; P = .432), and the 5-year disease-free survival was 25% (standard resection: 34%; P = .716). Radical resection was associated with 5-year overall survival of 51% and 5-year disease-specific survival of 75%.

CONCLUSION

This is the largest single-center analysis evaluating perioperative and long-term outcomes of portal vein resection for pancreatic neuroendocrine neoplasms. The postoperative complication rate after portal vein resection is comparable with standard resection. The 90-day mortality is low. Radical resection leads to excellent 5-year oncological survival.

Tumor vascularity on contrast-enhanced computed tomography as a predictive marker of metastatic potential for small nonfunctioning pancreatic neuroendocrine tumors

BACKGROUND

Although surgical resection is generally suggested for nonfunctioning pancreatic neuroendocrine tumors, observation can be proposed for carefully selected patients with small tumors. However, the indications for observation remain unclear.

METHODS

This retrospective study included 77 patients with nonfunctioning pancreatic neuroendocrine tumors, including small tumors (≤2.0 cm, n = 41), who received pancreatectomy. The ratio of the mean computed tomography value of a tumor in the late arterial/equilibrium phase (computed tomography a/e ratio) was used to evaluate tumor vascularity. Pathologic examinations of small tumors were conducted. The associations among the computed tomography a/e ratio, pathologic findings, and survival outcomes were investigated.

RESULTS

Small tumors were pathologically categorized by the degree of fibrosis as follows: medullary (n = 20), intermediate (n = 11), and fibrotic (n = 10). The fibrotic type had significantly lower computed tomography a/e ratios than the medullary type (median, 1.42 vs 2.03, P < .001). The median number of vessels with microscopic venous invasion was significantly higher in the fibrotic type than in the medullary type (4.5 vs 0.0, P < .001). The cutoff value of the computed tomography a/e ratio for predicting microscopic venous invasion was determined to be 1.54 by the receiver operating characteristic curve (area under the curve, 0.832; sensitivity, 80.0%; specificity, 83.9%; accuracy, 82.9%). Microscopic venous invasion was an independent prognostic factor for relapse-free survival in overall patients (hazard ratio 5.18, P = .017).

CONCLUSION

The computed tomography a/e ratio may be a useful predictor of the metastatic potential of nonfunctioning pancreatic neuroendocrine tumors and may help decide the indications of observation for small nonfunctioning pancreatic neuroendocrine tumors.

An integrative view on glucagon function and putative role in the progression of pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC)

Cancer metabolism research area evolved greatly, however, is still unknown the impact of systemic metabolism control and diet on cancer. It makes sense that systemic regulators of metabolism can act directly on cancer cells and activate signalling, prompting metabolic remodelling needed to sustain cancer cell survival, tumour growth and disease progression. In the present review, we describe the main glucagon functions in the control of glycaemia and of metabolic pathways overall. Furthermore, an integrative view on how glucagon and related signalling pathways can contribute for pancreatic neuroendocrine tumours (pNETs) and hepatocellular carcinomas (HCC) progression, since pancreas and liver are the major organs exposed to higher levels of glucagon, pancreas as a producer and liver as a scavenger. The main objective is to bring to discussion some glucagon-dependent mechanisms by presenting an integrative view on microenvironmental and systemic aspects in pNETs and HCC biology.

Surgical Management of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) are relatively uncommon malignancies, characterized as either functional or nonfunctional secondary to their secretion of biologically active hormones. A wide range of clinical behavior can be seen, with the primary prognostic indicator being tumor grade as defined by the Ki67 proliferation index and mitotic index. Surgery is the primary treatment modality for PNETs. While functional PNETs should undergo resection for symptom control as well as potential curative intent, nonfunctional PNETs are increasingly managed nonoperatively. There is increasing data to suggest small, nonfunctional PNETs (less than 2 cm) are appropriate follow with nonoperative active surveillance. Evidence supports surgical management of metastatic disease if possible, and occasionally even surgical management of the primary tumor in the setting of widespread metastases. In this review, we highlight the evolving surgical management of local and metastatic PNETs.

Lymph node metastases and recurrence in pancreatic neuroendocrine neoplasms

BACKGROUND

The impact of lymph node metastasis on survival in pancreatic neuroendocrine neoplasms as well as their best surgical treatment is controversial. We aimed to determine the frequency and prognostic impact of lymph node involvement in pancreatic neuroendocrine neoplasms.

METHODS

Patients undergoing pancreatic resections for pancreatic neuroendocrine neoplasms between 2001 and 2019 were retrospectively analyzed based on a prospective database. Clinicopathological parameters and perioperative outcome were assessed. Overall and disease-free survival was analyzed. Subgroup analysis was performed for sporadic, nonfunctional pancreatic neuroendocrine neoplasms without distant metastases and ≥4 analyzed lymph nodes.

RESULTS

Of 605 surgically resected pancreatic neuroendocrine neoplasms, 55% were G1, 36% were G2, and 9% were G3 differentiated. At the time of resection, 34% of patients had lymph node metastasis, and 16% had distant metastases. For subgroup analysis, 314 patients were analyzed. Lymph node metastases occurred in 36% of patients and were most frequent in G3 patients (67%). An increase in tumor size and advancement was associated with higher rates of lymph node metastasis, and disease-free survival was significantly impaired. Significant differences in disease-free survival were observed between 1 and 3 (5-year disease-free survival 52%) and ≥4 positive lymph nodes (5-year disease-free survival 28%), as well as when G3 tumors were excluded. In multivariable analysis, grading, tumor stage, and especially lymph node metastases as well as the proposed pN1 and pN2 categories were confirmed as independent predictors of recurrence.

CONCLUSION

The presence and extent of lymph node involvement has considerable prognostic impact in pancreatic neuroendocrine neoplasms. This study, for the first time, validated the proposed pN2 stage for well-differentiated pancreatic neuroendocrine neoplasms.

Enucleation Is a Feasible Procedure for Well-Differentiated pNEN-A Matched Pair Analysis

The extent of surgical resection in the treatment of pancreatic neuroendocrine neoplasms (pNEN) is still controversial. This study aimed to evaluate the outcomes of enucleation for well-differentiated non-functional (nf) pNEN. Patients undergoing enucleation (2001−2020) were analyzed. Clinicopathological parameters, perioperative outcomes and survival were assessed. The analysis was performed as a nested case-control study and matched-pair analysis with formal resection. Sixty-one patients undergoing enucleation were identified. Compared to patients undergoing formal resection, enucleation was associated with a significantly shorter median length of operative time (128 (IQR 95−170) versus 263 (172−337) minutes, p < 0.0001) and a significantly lower rate of postoperative diabetes (2% versus 21%, p = 0.0020). There was no significant difference in postoperative pancreatic fistula rate (18% versus 16% type B/C, p = 1.0), Clavien−Dindo ≥ III complications (20% versus 26%, p = 0.5189), readmission rate (12% versus 15%, p = 0.6022) or length of hospital stay (8 (7−11) versus 10 (8−17) days, p = 0.0652). There was no 30-day mortality after enucleation compared to 1.6% (n = 1) after formal resection. 10-year overall survival (OS) and disease-free survival (DFS) was similar between the two groups (OS: 89% versus 77%, p = 0.2756; DFS: 98% versus 91%, p = 0.0873). Enucleation presents a safe surgical approach for well-differentiated nf-pNEN with good long-term outcomes for selected patients.

Imaging findings of spontaneous intraabdominal hemorrhage: neoplastic and non-neoplastic causes

Contrary to traumatic and iatrogenic intraabdominal hemorrhages, spontaneous intraabdominal hemorrhage is a challenging clinical situation. A variety of neoplastic and non-neoplastic conditions may cause spontaneous intraabdominal bleeding. Imaging findings vary depending on the source of bleeding and the underlying cause. In this article, we aim to increase the awareness of imagers to the most common causes of spontaneous intraabdominal hemorrhage by using representative cases.

Surgical Treatment of Patients with Poorly Differentiated Pancreatic Neuroendocrine Carcinoma: An NCDB Analysis

BACKGROUND

Consensus guidelines discourage resection of poorly differentiated pancreatic neuroendocrine carcinoma (panNEC) given its association with poor long-term survival. This study assessed treatment patterns and outcomes for this rare malignancy using the National Cancer Database (NCDB).

METHODS

Patients with non-functional pancreatic neuroendocrine tumors in the NCDB (2004-2016) were categorized based on pathologic differentiation. Logistic and Cox proportional hazard regressions identified associations with resection and overall survival (OS). Survival was compared using Kaplan-Meier and log-rank tests.

RESULTS

Most patients (83%) in the cohort of 8560 patients had well-differentiated tumors (panNET). The median OS was 47 months (panNET, 63 months vs panNEC, 17 months; p < 0.001). Surgery was less likely for older patients (odds ratio [OR], 0.97), patients with panNEC (OR, 0.27), and patients with metastasis at diagnosis (OR, 0.08) (all p < 0.001). After propensity score-matching of these factors, surgical resection was associated with longer OS (82 vs 29 months; p < 0.001) and a decreased hazard of mortality (hazard ratio [HR], 0.37; p < 0.001). Surgery remained associated with longer OS when stratified by differentiation (98 vs 41 months for patients with panNET and 36 vs 8 months for patients with panNEC). Overall survival did not differ between patients with panNEC who underwent surgery and patients with panNET who did not (both 39 months; p = 0.294).

CONCLUSIONS

Poorly differentiated panNEC exhibits poorer survival than well-differentiated panNET. In the current cohort, surgical resection was strongly and independently associated with improved OS, suggesting that patients with panNEC who are suitable operative candidates should be considered for multimodality therapy, including surgery.

Impact of tumor grade on pancreatic neuroendocrine tumors

BACKGROUND/OBJECTIVE

Pancreatic neuroendocrine tumors (P-NETs) are highly heterogeneous with wide spectrum of biological behaviors and growth patterns. Here, we aimed to assess the impact of tumor grading on P-NETs prognosis and survival outcomes.

METHODS

Patients with P-NET were recruited to determine correlations between grades and clinicopathological factors, survival outcomes and prognostic factors.

RESULT

A total of 152 patients with P-NETs were enrolled. G1 P-NET were associated with significantly lower rates of perineural invasion, lymphovascular invasion, lymph node involvement and distant metastasis. The pancreatic head was the most common location of P-NETs. The 1-year, 5-year and 10-year overall survival rates of the patients were 94.4%, 89.1% and 78.8%, respectively. Majority of pancreatic neuroendocrine carcinoma (P-NEC) were unresectable (90.9%), and P-NECs patients had poor survival rates (1-year, 20% and no 5-year). Male sex, tumor size ≥2.5 cm, perineural invasion, lymph node invasion, metastasis, and advanced stage were significantly associated with poorer survival outcomes. Tumor grade and sex were independent survival predictors. Moreover, tumor grade was the most powerful prognostic factor.

CONCLUSIONS

Tumor grade, sex, perineural invasion, tumor size, lymph node involvement, metastasis, and stage are survival predictors for patients with P-NETs. Tumor grade is the most powerful independent prognostic factor.

Racial disparities in operative management of localized, non-functional pancreatic neuroendocrine tumors in surgically fit patients

BACKGROUND

Guidelines recommend resection of non-functional neuroendocrine tumors of the pancreas (NF-pNETs) that are ≥2 cm in size. We compared utilization of surgery based on race.

METHODS

We identified non-Hispanic White and Black patients with localized NF-pNETs ≥2 cm and Charlson-Deyo score 0-1 in the NCDB (2004-2016). We compared utilization of surgery by race, adjusting for clinicodemographic variables. Overall survival was compared based on management.

RESULTS

A total of 3459 patients were included (White = 3005; Black = 454). Black patients were younger (58vs63 years) and more often treated at academic facilities (65.3%vs60.3%). Overall, Black and White patients underwent surgery at similar rates (77.3%vs79.6%). When stratified by primary site, Black patients with body/tail tumors were less likely to undergo surgery (78.5%vs84.7%). On multivariable analysis, Black race was associated with a lower likelihood of surgery overall (OR 0.74,p = 0.034) and in patients with body/tail tumors (OR 0.56,p = 0.001). Non-operative management was associated with a higher risk of death (HR 3.19,p < 0.001).

CONCLUSION

In a national cohort of patients with NF-pNETs meeting criteria for resection, Black race is associated with lower frequency of surgery. Operative intervention is associated with prolonged survival. Persistent racial disparities in management of a surgically curable disease should be targeted for improvement.

Imaging of Pancreatic Neuroendocrine Neoplasms

Pancreatic neuroendocrine neoplasms (panNENs) represent the second most common pancreatic tumors. They are a heterogeneous group of neoplasms with varying clinical expression and biological behavior, from indolent to aggressive ones. PanNENs can be functioning or non-functioning in accordance with their ability or not to produce metabolically active hormones. They are histopathologically classified according to the 2017 World Health Organization (WHO) classification system. Although the final diagnosis of neuroendocrine tumor relies on histologic examination of biopsy or surgical specimens, both morphologic and functional imaging are crucial for patient care. Morphologic imaging with ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI) is used for initial evaluation and staging of disease, as well as surveillance and therapy monitoring. Functional imaging techniques with somatostatin receptor scintigraphy (SRS) and positron emission tomography (PET) are used for functional and metabolic assessment that is helpful for therapy management and post-therapeutic re-staging. This article reviews the morphological and functional imaging modalities now available and the imaging features of panNENs. Finally, future imaging challenges, such as radiomics analysis, are illustrated.

Updated Trends in Imaging Practices for Pancreatic Neuroendocrine Tumors (PNETs): A Systematic Review and Meta-Analysis to Pave the Way for Standardization in the New Era of Big Data and Artificial Intelligence

Purpose

Medical imaging plays a central and decisive role in guiding the management of patients with pancreatic neuroendocrine tumors (PNETs). Our aim was to synthesize all recent literature of PNETs, enabling a comparison of all imaging practices.

Methods

based on a systematic review and meta-analysis approach, we collected; using MEDLINE, EMBASE, and Cochrane Library databases; all recent imaging-based studies, published from December 2014 to December 2019. Study quality assessment was performed by QUADAS-2 and MINORS tools.

Results

161 studies consisting of 19852 patients were included. There were 63 ‘imaging’ studies evaluating the accuracy of medical imaging, and 98 ‘clinical’ studies using medical imaging as a tool for response assessment. A wide heterogeneity of practices was demonstrated: imaging modalities were: CT (57.1%, n=92), MR (42.9%, n=69), PET/CT (13.3%, n=31), and SPECT/CT (9.3%, n=15). International imaging guidelines were mentioned in 2.5% (n=4/161) of studies. In clinical studies, imaging protocol was not mentioned in 30.6% (n=30/98) of cases and only mentioned imaging modality without further information in 63.3% (n=62/98), as compared to imaging studies (1.6% (n=1/63) of (p<0.001)). QUADAS-2 and MINORS tools deciphered existing biases in the current literature.

Conclusion

We provide an overview of the updated current trends in use of medical imaging for diagnosis and response assessment in PNETs. The most commonly used imaging modalities are anatomical (CT and MRI), followed by PET/CT and SPECT/CT. Therefore, standardization and homogenization of PNETs imaging practices is needed to aggregate data and leverage a big data approach for Artificial Intelligence purposes.

Sunitinib-Loaded Chondroitin Sulfate Hydrogels as a Novel Drug-Delivery Mechanism for the Treatment of Pancreatic Neuroendocrine Tumors

BACKGROUND

Pancreatic neuroendocrine tumors (PanNETs) are increasingly common. Experts debate whether small tumors should be resected. Tumor destruction via injection of cytotoxic agents could offer a minimal invasive approach to this controversy. We hypothesize that a new drug delivery system comprising chondroitin sulfate (CS) hydrogels loaded with sunitinib (SUN) suppresses tumor growth in PanNET cells.

METHODS

Injectable hydrogels composed of CS modified with methacrylate groups (MA) were fabricated and loaded with SUN. Loading target was either 200 µg (SUN200-G) or 500 µg (SUN500-G) as well as sham hydrogel with no drug loading (SUN0-G). SUN release from hydrogels was monitored in vitro over time and cytotoxicity induced by the released SUN was evaluated using QGP-1 and BON1 PanNET cell lines. QGP-1 xenografts were developed in 35 mice and directly injected with 25 µL of either SUN200-G, SUN500-G, SUN0-G, 100 µL of Sunitinib Malate (SUN-inj), or given 40 mg/kg/day oral sunitinib (SUN-oral).

RESULTS

SUN-loaded CSMA hydrogel retained complete in vitro cytotoxicity toward the QGP-1 PanNET and BON-1 PanNET cell lines for 21 days. Mouse xenograft models with QGP-1 PanNETs showed a significant delay in tumor growth in the SUN200/500-G, SUN-inj and SUN-oral groups compared with SUN0-G (p = 0.0014). SUN500-G hydrogels induced significantly more tumor necrosis than SUN0-G (p = 0.04). There was no difference in tumor growth delay between SUN200/500G, SUN-inj, and SUN-oral.

CONCLUSIONS

This study demonstrates that CSMA hydrogels loaded with SUN suppress PanNETs growth. This drug delivery could approach represents a novel way to treat PanNETs and other neoplasms via intratumoral injection.

A novel classification of portal venous tumor invasion to predict residual tumor status after surgery in patients with pancreatic neuroendocrine neoplasms

PURPOSE

To elucidate whether portal venous tumor invasion (PVTI) is a prognostic factor for patients with pancreatic neuroendocrine neoplasms (Pan-NENs).

METHODS

From 2002 to 2019, 240 patients with Pan-NEN were included to examine prognostic factors. PVTI based on computed tomography (CT) images are classified into four types: no PVTI (Vp0/1), PVTI not invading the superior mesenteric vein (Vp2), PVTI invading the superior mesenteric vein or portal vein (Vp3), and PVTI invading the portal bifurcation (Vp4).

RESULTS

Simultaneous liver metastases (SLM) determined the overall survival (OS) in 240 patients. The 5-year OS rates with and without SLM were 46% and 92%, respectively (P < 0.001). PVTIs were observed in 56 of the 240 patients (23%). Among such patients, 39, 11, and 6 had Vp2, Vp3, and Vp4, respectively. The 5-year OS rates with and without PVTI were 62% and 82%, respectively (P < 0.001). Severity of PVTI did not decide PFS and OS after R0/1 resection. There was significant difference in the prognoses between Vp0/1 and Vp2-4. In 161 patients without SLM, 21 had PVTI (13%). According to a multivariate analysis, PVTI and Ki-67 index were independent prognostic factors for progression-free survival (PFS) in patients without SLM. The 5-year PFS rates with and without PVTI were 18% and 77%, respectively (P < 0.001). The 5-year OS rates with and without PVTI were 76% and 95%, respectively (P = 0.02). PVTI was associated with tumor functionality, high serum NSE, and high Ki-67 index.

CONCLUSIONS

PVTI may be a predictor for postoperative recurrence.

Development and comparison of novel bioluminescent mouse models of pancreatic neuroendocrine neoplasm metastasis

Pancreatic neuroendocrine neoplasms (pNENs) are slow growing cancers of increasing incidence that lack effective treatments once they become metastatic. Unfortunately, nearly half of pNEN patients present with metastatic liver tumors at diagnosis and current therapies fail to improve overall survival. Pre-clinical models of pNEN metastasis are needed to advance our understanding of the mechanisms driving the metastatic process and for the development of novel, targeted therapeutic interventions. To model metastatic dissemination of tumor cells, human pNEN cell lines (BON1 and Qgp1) stably expressing firefly luciferase (luc) were generated and introduced into NSG immunodeficient mice by intracardiac (IC) or intravenous (IV) injection. The efficiency, kinetics and distribution of tumor growth was evaluated weekly by non-invasive bioluminescent imaging (BLI). Tumors formed in all animals in both the IC and IV models. Bioluminescent Qgp1.luc cells preferentially metastasized to the liver regardless of delivery route, mimicking the predominant site of pNEN metastasis in patients. By comparison, BON1.luc cells most commonly formed lung tumors following either IV or IC administration and colonized a wider variety of tissues than Qgp1.luc cells. These models provide a unique platform for testing candidate metastasis genes and anti-metastatic therapies for pNENs.

Recurrence of Non-functional Pancreatic Neuroendocrine Tumors After Curative Resection: A Tumor Burden-Based Prediction Model

BACKGROUND

Patients can experience recurrence following curative-intent resection of non-functional pancreatic neuroendocrine tumors (NF-pNETs). We sought to develop a nomogram to risk stratify patients relative to recurrence following resection of NF-pNETs.

METHODS

Patients who underwent curative-intent resection for NF-pNETs between 1997 and 2016 were identified from a multi-institutional database. The impact of clinicopathologic factors, including tumor burden score (TBS) (TBS² = (maximum tumor diameter)² + (number of tumors)²), was assessed relative to recurrence-free survival (RFS), and a nomogram was developed and internally validated.

RESULTS

With a median follow-up of 31.0 months (IQR 11.3-56.6 months), 66 (15.8%) out of 416 patients in the cohort experienced tumor recurrence. Overall, 3-, 5-, and 10-year RFS following curative-intent resection was 83.2%, 74.0%, and 44.7%, respectively. Several factors were associated with risk of recurrence including tumor grade (referent G1: G2, HR 4.07, 95% CI 2.29-7.26, p < 0.001; G3, HR 10.83, 95% CI 3.72-31.53, p < 0.001), lymph node metastasis (LNM) (HR 4.71, 95% CI 2.69-8.26, p < 0.001), as well as TBS (referent low: medium, HR 4.36, 95% CI 2.06-9.24, p < 0.001; high, HR 6.04, 95% CI 2.96-12.31, p < 0.001). A weighted nomogram including tumor grade (G1 0, G2 54.19, G3 100), LNM (N0 0, N1 42.06), and TBS (low 0, medium 44.07, high 56.48) was developed. The discriminatory power of the nomogram was very good with a C-index of 0.75 (95% CI, 0.66-0.79) in the training cohort and 0.71 (95% CI, 0.65-0.75) in the validation cohort. In addition, the nomogram performed better than the current 8th edition of AJCC TNM staging system, which had a C-index of 0.67 (95% CI, 0.60-0.73).

CONCLUSIONS

A nomogram that incorporated tumor grade, LNM, and TBS was established that had good discrimination and calibration. The nomogram may be an effective tool to stratify patients relative to recurrence risk following resection of NF-pNETs.

Combined Hepatopancreaticobiliary Volume and Hepatectomy Outcomes in Hepatocellular Carcinoma Patients at Low-Volume Liver Centers

BACKGROUND

The relationship between hospital volume and surgical outcomes is well-established; however, considerable socioeconomic and geographic barriers to high-volume care persist. This study assesses how the overall volume of hepatopancreaticobiliary (HPB) cancer operations impacts outcomes of liver resections (LRs).

STUDY DESIGN

The National Cancer Database (2004-2014) was queried for patients who underwent LR for hepatocellular carcinoma. Hospital volume was determined separately for all HPB operations and LRs. Centers were dichotomized as low and high volume based on the median number of operations. The following study cohorts were created: low-volume hospitals (LVHs) for both LRs and HPB operations, mixed-volume hospitals (MVHs) with low-volume LRs but high-volume HPB operations, and high-volume LR hospitals (HVHs) for both LRs and HPB operations.

RESULTS

Of 7,265 patients identified, 37.5%, 8.8%, and 53.7% were treated at LVHs, MVHs, and HVHs, respectively. On multivariable analysis, patients treated at LVHs had higher 30-day mortality compared with patients treated at HVHs (odds ratio 1.736; p < 0.001). However, patients treated at MVHs experienced 30-day mortality comparable with patients treated at HVHs (odds ratio 0.789; p = 0.318). Similar results were found for positive margin status, prolonged hospital stay, and overall survival.

CONCLUSIONS

LR outcomes at low-volume LR centers that have substantial experience with HPB cancer operations are similar to those at high-volume LR centers. Our results demonstrate that the volume to outcomes curve for HPB operations should be assessed more holistically and that patients can safely undergo liver operations at low-volume LR centers if HPB volume criteria are met.

Volume of Pancreas-Adjacent Operations Favorably Influences Pancreaticoduodenectomy Outcomes at Lower Volume Pancreas Centers

OBJECTIVE

This study assesses how the volume of pancreatic-adjacent operations (PAO) impacts the outcomes of pancreaticoduodenectomy (PD).

SUMMARY BACKGROUND DATA

It is well-established that regionalization benefits outcomes after PD. However, due to a multitude of factors, including geographic, financial and personal, not all patients receive their care at high-volume pancreas surgery centers.

METHODS

The National Cancer Database was queried for pancreatic cancer patients who underwent pancreaticoduodenectomy. Hospital volume was calculated for PD and PAO (defined as gastric, hepatic, complex biliary, or pancreatic operations other than PD) and dichotomized as low- and high-volume centers based on the median. Three study cohort were created: low-volume hospitals (LVH) for both PD and PAO, mixed-volume hospital (MVH) with low-volume PD but high-volume PAO, and high-volume PD hospital (HVH).

RESULTS

In total, 24,572 patients were identified, with 41.5%, 7.2%, and 51.3% patients treated at LVH, MVH, and HVH, respectively. 30-day mortality for PD was 5.6% in LVH, 3.2% in MVH, and 2.5% in HVH. On multivariable analyses, LVH was predictive for higher 30-day mortality compared to HVH (OR, 2.068; 95% CI, 1.770-2.418; p < 0.0001). However, patients at MVH demonstrated similar 30-day mortality to patients treated at HVH (OR, 1.258; 95% CI, 0.942-1.680; p = 0.1203).

CONCLUSIONS

PD outcomes at low-volume centers that have experience with complex cancer operations near the pancreas are similar to PD outcomes at hospitals with high PD volume. MVH provide a model for PD outcomes to improve quality and access for patients who cannot, or choose not to, receive their care at high-volume centers.

Tumor burden score predicts tumor recurrence of non-functional pancreatic neuroendocrine tumors after curative resection

BACKGROUND

To investigate the feasibility of Tumor Burden Score (TBS) to predict tumor recurrence following curative-intent resection of non-functional pancreatic neuroendocrine tumors (NF-pNETs).

METHOD

The TBS cut-off values were determined by a statistical tool, X-tile. The influence of TBS on recurrence-free survival (RFS) was examined.

RESULTS

Among 842 NF-pNETs patients, there was an incremental worsening of RFS as the TBS increased (5-year RFS, low, medium, and high TBS: 92.0%, 73.3%, and 59.3%, respectively; P < 0.001). TBS (AUC 0.74) out-performed both maximum tumor size (AUC 0.65) and number of tumors (AUC 0.5) to predict RFS (TBS vs. maximum tumor size, p = 0.05; TBS vs. number of tumors, p < 0.01). The impact of margin (low TBS: R0 80.4% vs. R1 71.9%, p = 0.01 vs. medium TBS: R0 55.8% vs. R1 37.5%, p = 0.67 vs. high TBS: R0 31.9% vs. R1 12.0%, p = 0.11) and nodal (5-year RFS, low TBS: N0 94.9% vs. N1 68.4%, p < 0.01 vs. medium TBS: N0 81.8% vs. N1 55.4%, p < 0.01 vs. high TBS: N0 58.0% vs. N1 54.2%, p = 0.15) status on 5-year RFS outcomes disappeared among patients who had higher TBS.

CONCLUSIONS

TBS was strongly associated with risk of recurrence and outperformed both tumor size and number alone.

Predicting Aggressive Behavior in Nonfunctional Pancreatic Neuroendocrine Tumors With Emphasis on Tumor Size Significance and Survival Trends: A Population-Based Analysis of 1787 Patients

BACKGROUND

Nonfunctional pancreatic neuroendocrine tumors (NF-PNETs) are rare tumors with continued controversies in management. This study aims to identify demographic and clinicopathologic characteristics associated with aggressive behavior and survival.

METHODS

The Surveillance, Epidemiology, and End Results database was used to identify patients with NF-PNETs from 1988 to 2012. Multivariate regression analysis and Cox proportional hazards modeling were used to assess the impact of patient, tumor, and treatment characteristics on tumor behavior and overall survival.

RESULTS

In 1787 patients identified, size was a major determinant of aggressive behavior. The probability of aggressiveness increased 100% for tumor size ≥2 cm. For tumors ≥2 cm, every 1-cm increase in size was associated with an increase in probability of aggressive behavior by 11.3%. Patient age, tumor grade, and surgical resection were independent predictors of survival. Surgical resection was associated with improved survival but not grade I or II tumors with size <2 cm.

DISCUSSION

Patient age, tumor size, and grade should be in the decision-making process around the surgical management of NF-PNETs. For tumors ≤2 cm with histologic grades of I or II, the probability of aggressive behavior is low, and surgical resection does not appear to afford survival benefit. Therefore, close observation could be justified.

Morphological imaging and CT histogram analysis to differentiate pancreatic neuroendocrine tumor grade 3 from neuroendocrine carcinoma

PURPOSE

To compare morphological imaging features and CT texture histogram parameters between grade 3 pancreatic neuroendocrine tumors (G3-NET) and neuroendocrine carcinomas (NEC).

MATERIALS AND METHODS

Patients with pathologically proven G3-NET and NEC, according to the 2017 World Health Organization classification who had CT and MRI examinations between 2006-2017 were retrospectively included. CT and MRI examinations were reviewed by two radiologists in consensus and analyzed with respect to tumor size, enhancement patterns, hemorrhagic content, liver metastases and lymphadenopathies. Texture histogram analysis of tumors was performed on arterial and portal phase CT images. images. Morphological imaging features and CT texture histogram parameters of G3-NETs and NECs were compared.

RESULTS

Thirty-seven patients (21 men, 16 women; mean age, 56±13 [SD] years [range: 28-82 years]) with 37 tumors (mean diameter, 60±46 [SD] mm) were included (CT available for all, MRI for 16/37, 43%). Twenty-three patients (23/37; 62%) had NEC and 14 patients (14/37; 38%) had G3-NET. NECs were larger than G3-NETs (mean, 70±51 [SD] mm [range: 18 - 196mm] vs. 42±24 [SD] mm [range: 8 - 94mm], respectively; P=0.039), with more tumor necrosis (75% vs. 33%, respectively; P=0.030) and lower attenuation on precontrast (30±4 [SD] HU [range: 25-39 HU] vs. 37±6 [SD] [range: 25-45 HU], respectively; P=0.002) and on portal venous phase CT images (75±18 [SD] HU [range: 43 - 108 HU] vs. 92±19 [SD] HU [range: 46 - 117 HU], respectively; P=0.014). Hemorrhagic content on MRI was only observed in NEC (P=0.007). The mean ADC value was lower in NEC ([1.1±0.1 (SD)]×10^-3 mm²/s [range: (0.91 - 1.3)×10^-3 mm²/s] vs. [1.4±0.2 (SD)]×10^-3 mm²/s [range: (1.1 - 1.6)×10^-3 mm²/s]; P=0.005). CT histogram analysis showed that NEC were more heterogeneous on portal venous phase images (Entropy-0: 4.7±0.2 [SD] [range: 4.2-5.1] vs. 4.5±0.4 [SD] [range: 3.7-4.9]; P=0.023).

CONCLUSION

Pancreatic NECs are larger, more frequently hypoattenuating and more heterogeneous with hemorrhagic content than G3-NET on CT and MRI.

p53-PHLDA3-Akt Network: The Key Regulators of Neuroendocrine Tumorigenesis

p53 is a well-known tumor suppressor gene and one of the most extensively studied genes in cancer research. p53 functions largely as a transcription factor and can trigger a variety of antiproliferative programs via induction of its target genes. We identified PHLDA3 as a p53 target gene and found that its protein product is a suppressor of pancreatic neuroendocrine tumors (PanNETs) and a repressor of Akt function. PHLDA3 is frequently inactivated by loss of heterozygosity (LOH) and methylation in human PanNETs, and LOH at the PHLDA3 gene locus correlates with PanNET progression and poor prognosis. In addition, in PHLDA3-deficient mice, pancreatic islet cells proliferate abnormally and acquire resistance to apoptosis. In this article, we briefly review the roles of p53 and Akt in human neuroendocrine tumors (NETs) and describe the relationship between the p53-PHLDA3 and Akt pathways. We also discuss the role of PHLDA3 as a tumor suppressor in various NETs and speculate on the possibility that loss of PHLDA3 function may be a useful prognostic marker for NET patients indicating particular drug therapies. These results suggest that targeting the downstream PHLDA3-Akt pathway might provide new therapies to treat NETs.

Grade 3 Pancreatic Neuroendocrine Tumors on MDCT: Establishing a Diagnostic Model and Comparing Survival Against Pancreatic Ductal Adenocarcinoma

OBJECTIVE. The purpose of this study is to establish a diagnostic model for differentiating grade 3 (G3) pancreatic neuroendocrine tumors (PNETs) from pancreatic ductal adenocarcinomas (PDACs) and to analyze survival outcomes. MATERIALS AND METHODS. Twenty patients with G3 PNETs and 58 patients with PDACs confirmed by surgery or biopsy were retrospectively included. Demographic and radiologic information was collected. Univariate analyses and binary logistic regression analyses were performed to identify independent factors and establish a diagnostic model. An ROC curve was created to determine diagnostic ability. Kaplan-Meier survival analysis was performed. RESULTS. Patients with G3 PNETs were more likely to present with normal carbohydrate antigen (CA) 19-9 levels, normal pancreatic ducts, and round tumors with well-defined margins and higher portal enhancement ratios than were patients with PDAC (p < 0.05). After multivariate analysis, a normal CA 19-9 level (odds ratio, 0.0125; 95% CI, 0.0008-0.2036), round tumor shape (odds ratio, 0.0143; 95% CI, 0.0004-0.5461), and pancreatic duct dilation of 4 mm or less (odds ratio, 17.9804; 95% CI, 1.0098-320.1711) were independent predictors of G3 PNETs. The AUC of the ROC curve was 0.916, and sensitivity and specificity were 90.0% and 81.0%, respectively. Furthermore, patients with G3 PNETs had better overall survival than patients with PDACs. Among patients in the G3 PNET subgroup, patients with liver or lymph node metastases had worse overall survival than patients without metastases. CONCLUSION. A diagnostic model was established to differentiate G3 PNETs from PDACs. A normal CA 19-9 level, round tumor shape, and pancreatic duct dilation of 4 mm or less were factors that were strongly predictive of G3 PNET.

Serotonin-Secreting Neuroendocrine Tumours of the Pancreas

Background: Serotonin-secreting pancreatic neuroendocrine tumours (5-HT-secreting pNETs) are very rare, and characterised by high urinary 5-hydroxyindole-acetic acid (5-HIAA) levels (or high serum 5-HT levels). Methods: Patients with 5-HT-secreting pancreatic neoplasms observed in our unit (1986–2015) were included. Diagnosis was based on urinary 5-HIAA or serum 5-HT levels. Results: Seven patients were enrolled (4 M/3 F), with a median age of 64 (range 38–69) years. Two patients had a carcinoid syndrome. Serum 5-HT was elevated in four patients. Urinary 5-HIAA levels were positive in six patients. The median tumour size was 4.0 (range 2.5–10) cm. All patients showed liver metastases at diagnosis. None underwent resective surgery; lymph node/liver biopsies were taken. Six lesions were well-differentiated tumours and one a poorly differentiated carcinoma (Ki67 range 3.4–70%). All but one patient received chemotherapy. Four patients received somatostatin analogues; three patients underwent ablation of liver metastases. One patient is alive with disease 117 months after observation. All the others died from disease progression after a follow-up within 158 months. Conclusions: Primary 5-HT-secreting pNETs are mostly metastatic to the liver; patients are not amenable to resective surgery. Despite high 5-HIAA urinary levels, few patients present with carcinoid syndrome. A five-year survival rate of 42.9% may be achieved with multimodal treatment.

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.

Update on the Surgical Treatment of Pancreatic Neuroendocrine Tumors

BACKGROUND AND AIMS

Pancreatic neuroendocrine tumors (PNET) arise from uncontrolled proliferation of neuroendocrine cell and further genetic alterations that may induce hormone secretion such as glucagon/insulin/gastrin/VIP. Their incidence is rapidelly growing, especially because of the frequent incidental diagnosis of small asymptomatic non-functionnal neuroendocrine tumors with the widespread use of cross-sectional imaging. The vast majority of pancreatic neuroendocrine tumors are sporadic but up to 5%-10% of them arise from genetic syndromes, the main one being Multiple Endocrine Neopalsm type 1 (MEN1). Appropriate management of patients with PNET is a complex challenge for surgeons, and require extensive medical collaboration. This review aims to summarize major and recent updates regarding the medico-surgical management of PNETs.

MATERIAL AND METHODS

Review of pertinent English language literature.

RESULTS

This article provides a concise summary of the clinical presentation, diagnosis, surgical management, alternative treatments and follow up of PNETs.

CONCLUSION

PNET are a rare, heterogeneous group of neoplasms with a generally favorable prognosis at least compared to pancreatic adenocarcinoma. Surgical resection is the cornerstone of their management, particularly for localized disease, and should always be discussed in multidisciplinary tumor board.

A prognostic nomogram in patients with distant metastasis of pancreatic neuroendocrine tumors: a population-based study

Aim: Prognostic factors in patients with distant metastatic pancreatic neuroendocrine tumors (PNETs) remain uncertain. The purpose of our study is to establish a nomogram to predict survival outcomes in patients with metastatic PNETs. Methods: A total of 878 patients diagnosed with PNETs in the Surveillance, Epidemiology and End Results database between 2004 and 2016 were retrospectively identified. The Kaplan-Meier survival analysis with log-rank test was used to analyze survival outcomes. The nomogram was established after a univariate and multivariate Cox analysis. Results: The independent prognostic variables, including age, tumor grade and primary site surgery were applied to develop a nomogram. The original concordance index was 0.773 (95% CI: 0.751-0.795), and the bias-corrected concordance index was 0.769 (95% CI: 0.748-0.791). The internal calibration curves showed well consistency and veracity in predicting cancer-specific survival probabilities. Conclusion: A nomogram was constructed and verified to predict survival outcomes in patients with distant-stage PNETs.

Impact of tumour size on metastasis and survival in patients with pancreatic neuroendocrine tumours (PNETs): A population based study

Background: The relationship between tumour size and metastasis rate is poorly recognized in patients with pancreatic neuroendocrine tumours (PNETs). The impact of tumour size on prognosis was controversial in previous investigations.

Methods: PNETs cases diagnosed from 1988 to 2013 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. Clinicopathologic features were retrospectively analyzed. Survival was calculated by the Kaplan-Meier method. Multivariable Cox regression models with hazard ratios (HRs) were constructed to analyze survival outcomes and risk factors. Cubic spline analysis was used to assess relationship between tumor size and probability of metastasis.

Results: A total of 5424 patients were identified, 1226 (22.6%) with tumour size of 20mm or less. The probability of metastasis increased in a non-linear fashion with increasing tumour size. Univariate analysis showed that tumour size was significantly correlated with survival (P<0.001), no matter surgery was performed or not. However, subgroup analysis suggested this association to be linear for patients with localized and regional tumours (P<0.001), but stochastic in patients with distant stages (P=0.703). On multivariate analysis, tumour size was an indicator for metastasis (HR=1.010, 95%CI: 1.008-1.013, P<0.001) and size≤20mm was an independent prognostic factor for good survival. For tumours≤20mm, surgical treatment was associated with significantly improved survival (P<0.001).

Conclusions: Tumour size affects the probability of metastasis. Its prognostic impact on survival is restricted to patients with localized and regional disease. For patients with tumour size ≤20mm, surgical treatment should be considered preferably.

Duodenal neuroendocrine tumors: Somewhere between the pancreas and small bowel?

BACKGROUND

While sub-2 cm pancreatic neuroendocrine tumors (NETs) are often observed, small bowel-NETs undergo resection and lymphadenectomy regardless of size. Aim was to define the natural history of duodenal (D-NETs), determine the role of resection, and define the factors associated with overall survival (OS) after resection.

METHODS

National Cancer Database (2004-2014) was queried for the patients with nonmetastatic/nonfunctional D-NETs. Local resection (LR): local excision/polypectomy/excisional biopsy. Anatomic resection (AR): radical surgery. Tumor size was divided into less than 1 cm, 1 to 2 cm, and ≥2 cm. Propensity score weighting was used to create balanced resection and no-resection cohorts. The primary endpoint was OS.

RESULTS

Among 5502 patient, the median age was 65 years. The median follow-up was 49 months. The median tumor size was 0.8 cm. Resection was performed in 72% (n = 3954; LR: 61%, AR: 39%). Lymph node (LN) resection was performed in 26% (43% had metastasis). A total of 74% had negative margins. Resection and no-resection cohorts were propensity score weighted for age/sex/race/Charlson-Deyo score/tumor grade (all independently associated with OS on multivariable analysis). Resection was associated with improved median OS compared to no resection in all sizes (<1 cm: median not reached vs 194 months; 1-2 cm: median not reached vs 56 months; >2 cm: median not reached vs 90 months; all P < .01). Subset analysis of each resection size cohort demonstrated that neither type of resection, LN retrieval, LN positivity, or margin status was associated with OS (all P > .05).

CONCLUSION

Patients with nonmetastatic and nonfunctional D-NETS should be considered for resection regardless of tumor size. Given the lack of prognostic value, the resection type and extent of LN retrieval should be tailored to each patient's clinical picture and safety profile.

Novel Dual-Action Targeted Nanomedicine in Mice With Metastatic Thyroid Cancer and Pancreatic Neuroendocrine Tumors

Background

The advantages of nanomedicines include preferential delivery of the payload directly to tumor tissues. CYT-21625 is the novel, first-in-class gold nanomedicine designed to target tumor vasculature and cancer cells by specifically delivering recombinant human tumor necrosis factor alpha (rhTNF) and a paclitaxel prodrug.

Methods

We analyzed TNF receptor expression in publicly available gene expression profiling data and in thyroid tissue samples. Mice with metastatic FTC-133 and 8505C xenografts and the MEN1 conditional knock-out mice were treated weekly with CYT-21625 and gold nanoparticles with rhTNF only (CYT-6091); controls included mice treated with either paclitaxel or saline. In vivo luciferase activity was used to assess the effects on tumor growth. Computed tomography, magnetic resonance imaging, and 18F-Fludeoxyglucose positron emission tomography were used to study tumor selectivity in mice with insulin-secreting pancreatic neuroendocrine tumors (PNETs). All statistical tests were two-sided.

Results

Anaplastic thyroid cancer (ATC) expressed statistically significantly higher levels of TNF receptor superfamily 1A and 1B messenger RNA (n = 11) and protein (n = 6) than control samples (n = 45 and 13, respectively). Mice (n = 5-7 per group) with metastatic ATC (P < .009) and FTC-133 xenografts (P = .03 at week 3, but not statistically significant in week 4 owing to reduced sample size from death in non-CYT-21625 groups) treated with CYT-21625 had a statistically significantly lower tumor burden. Treatment with CYT-21625 resulted in loss of CD34 expression in intratumoral vasculature, decreased proliferating cell nuclear antigen, and increased cleaved caspase-3. Intratumoral vascular leakage occurred only in mice with PNET and ATC treated with CYT-6091 and CYT-21625. CYT-6091 and CYT-21625 preferentially deposited in PNETs and statistically significantly decreased serum insulin levels (n = 3 per group, P < .001). There were no toxicities observed in mice treated with CYT-21625.

Conclusions

CYT-21625 is effective in mice with PNETs and metastatic human thyroid cancer with no toxicities. Thus, CYT-21625 should be studied in patients with advanced PNETs and thyroid cancer.

A Prognostic Scoring System for the Prediction of Metastatic Recurrence Following Curative Resection of Pancreatic Neuroendocrine Tumors

BACKGROUND

Patients with early-stage pancreatic neuroendocrine tumors (PNETs) may develop metastatic recurrences despite undergoing potentially curative pancreas resections. We sought to identify factors predictive of metastatic recurrences and develop a prognostication strategy to predict recurrence-free survival (RFS) in resected PNETs.

METHODS

Patients with localized PNETs undergoing surgical resection between 1989 and 2015 were identified. Univariate and multivariate analysis were used to identify potential predictors of post-resection metastasis. A score-based prognostication system was devised using the identified factors. The bootstrap model validation methodology was utilized to estimate the external validity of the proposed prognostication strategy.

RESULTS

Of the 140 patients with completely resected early-stage PNETs, overall 5- and 10-year RFS were 84.6% and 67.1%, respectively. The median follow-up was 56 months. Multivariate analysis identified tumor size > 5 cm, Ki-67 index 8-20%, lymph node involvement, and high histologic grade (G3, or Ki-67 > 20%) as independent predictors of post-resection metastatic recurrence. A scoring system based on these factors stratified patients into three prognostic categories with distinct 5-year RFS: 96.9%, 54.8%, and 33.3% (P < 0.0001). The bootstrap model validation methodology projected our proposed prognostication strategy to retain a high predictive accuracy even when applied in an external dataset (validated c-index of 0.81).

CONCLUSIONS

The combination of tumor size, LN status, grade, and Ki-67 was identified as the most highly predictive indicators of metastatic recurrences in resected PNETs. The proposed prognostication strategy may help stratify patients for adjuvant therapies, enhanced surveillance protocols and future clinical trials.

Non-functional pancreatic neuroendocrine tumours: emerging trends in incidence and mortality

BACKGROUND

Our aim was to determine the epidemiology and recent changes in the trends of non-functional pancreatic neuroendocrine tumours (NF-pNETs) at the population level. In addition, we explored the risk factors that are associated with survival duration.

METHODS

Cases were identified form the Surveillance, Epidemiology, and End Results (SEER) Programme database from 2000 to 2014. Data on incidence and incidence-based (IB) mortality for NF-pNET were obtained from this database. Secular trends in age-adjusted incidence and IB mortality were determined by using the Joinpoint Regression program. Data analyses were performed using chi-square tests, Kaplan-Meier curves and Cox proportional hazards regression.

RESULTS

Overall, 4766 patients diagnosed with NF-pNET with a median age of 59 years were identified through our descriptive criteria. Caucasian patients accounted for the majority of the study population, and the proportion of patients with distant disease significantly decreased during our study period. Overall, there was an increase in incidence and IB mortality for NF-pNET; however, the rate of increase decreased during the recent years. In addition, the incidence trends of NF-pNET located in the pancreatic head significantly increased, and rates fo increase in IB mortality for NF-pNET in the pancreatic tail decreased in recent years. Additionally, the 1-, 5-, and 10-year survival rates were 79.0, 51.8, 38.1%, respectively. Furthermore, patient age, tumour grade, stage at diagnosis, tumour size, tumour site and resection were associated with mortality.

CONCLUSION

Despite increases in incidence and IB mortality, the rate of change in IB mortality for NF-pNET has decreased in recent years. Survival duration displayed a secular increase during the overall period, and the prognosis and survival duration of patients were closely related to the time of diagnosis, age of the patients and size and location of the tumour. Appropriate treatment adjustments based on tumour stage may thus facilitate improvements in patient outcomes.

Natural History and Treatment Trends in Pancreatic Cancer Subtypes

BACKGROUND

While pancreatic ductal adenocarcinoma is the most common form of pancreatic cancer, many other histologic forms of pancreatic cancer are also recognized. These histologic variants portray unique characteristics in terms of patient demographics, tumor behavior, survival, and responsiveness to treatments.

MATERIALS AND METHODS

Patients who underwent surgical resection of the pancreas for non-metastatic, invasive pancreatic cancer between 2004 and 2014 were selected from the National Cancer Data Base and categorized by histologic variant according to WHO classification guidelines. Patient demographics, tumor variables, treatment characteristics, and survival were compared between histologic groups and subgroups.

RESULTS

A total of 57,804 patients met inclusion and exclusion criteria and were grouped into eight major histologic categories. Survival analysis by the histologic group showed median overall survival of 20.2 months for ductal adenocarcinoma, 20.5 months for squamous cell carcinoma, 26.8 months for mixed acinar-neuroendocrine carcinomas, 52.6 months for cystic mucinous neoplasms with an associated invasive carcinoma, 67.5 months for acinar cell carcinoma, and 69.3 months for mesenchymal tumors. Median survival was not reached for neuroendocrine tumors and solid-pseudopapillary neoplasms, with 5-year overall survival rates of 84% and 97% respectively.

CONCLUSIONS

Rare subtypes of pancreatic cancer present unique clinicopathologic characteristics and display distinct tumor biologies. This study presents data on demographic, prognostic, treatment, and survival outcomes between rare forms of pancreatic neoplasms in order to aid understanding of the natural history and behavior of these neoplasms, with the hope of serving as a reference in clinical decision-making and ability to provide accurate prognostic information to patients.

RABL6A inhibits tumor-suppressive PP2A/AKT signaling to drive pancreatic neuroendocrine tumor growth

Hyperactivated AKT/mTOR signaling is a hallmark of pancreatic neuroendocrine tumors (PNETs). Drugs targeting this pathway are used clinically, but tumor resistance invariably develops. A better understanding of factors regulating AKT/mTOR signaling and PNET pathogenesis is needed to improve current therapies. We discovered that RABL6A, a new oncogenic driver of PNET proliferation, is required for AKT activity. Silencing RABL6A caused PNET cell-cycle arrest that coincided with selective loss of AKT-S473 (not T308) phosphorylation and AKT/mTOR inactivation. Restoration of AKT phosphorylation rescued the G1 phase block triggered by RABL6A silencing. Mechanistically, loss of AKT-S473 phosphorylation in RABL6A-depleted cells was the result of increased protein phosphatase 2A (PP2A) activity. Inhibition of PP2A restored phosphorylation of AKT-S473 in RABL6A-depleted cells, whereas PP2A reactivation using a specific small-molecule activator of PP2A (SMAP) abolished that phosphorylation. Moreover, SMAP treatment effectively killed PNET cells in a RABL6A-dependent manner and suppressed PNET growth in vivo. The present work identifies RABL6A as a new inhibitor of the PP2A tumor suppressor and an essential activator of AKT in PNET cells. Our findings offer what we believe is a novel strategy of PP2A reactivation for treatment of PNETs as well as other human cancers driven by RABL6A overexpression and PP2A inactivation.

Distinct genome-wide methylation patterns in sporadic and hereditary nonfunctioning pancreatic neuroendocrine tumors

BACKGROUND

Aberrant methylation is a known cause of cancer initiation and/or progression. There are scant data on the genome-wide methylation pattern of nonfunctioning pancreatic neuroendocrine tumors (NFPanNETs) and sporadic and hereditary NFPanNETs.

METHODS

Thirty-three tissue samples were analyzed: they included samples from sporadic (n = 9), von Hippel-Lindau (VHL)-related (n = 10), and multiple endocrine neoplasia type 1 (MEN1)-related NFPanNETs (n = 10) as well as normal islet cells (n = 4) for comparison. Genome-wide CpG methylation profiling was performed with the Infinium MethylationEPIC BeadChip assay and was analyzed with R-based tools.

RESULTS

In unsupervised hierarchical clustering, sporadic and MEN1-related NFPanNETs clustered together, and the VHL group was in a separate cluster. MEN1-related NFPanNETs had a higher rate of hypermethylated CpG sites in comparison with sporadic and VHL-related tumor groups. Differentially methylated region analysis confirmed the higher rate of hypermethylation in MEN1-related tumors. Moreover, in an integrated analysis of gene expression data for the same tumor samples, downregulated gene expression was found in most genes that were hypermethylated. In a CpG island methylator phenotype analysis, 3 genes were identified and confirmed to have downregulated gene expression: secreted frizzle-related protein 5 (SFRP5) in sporadic NFPanNETs and cell division cycle-associated 7-like (CDCA7L) and RNA binding motif 47 (RBM47) in MEN1-related NFPanNETs.

CONCLUSIONS

MEN1 NFPanNETs have a higher rate of geno me-wide hypermethylation than other NFPanNET subtypes. The similarity between the pathways enriched in a methylation analysis of known genes involved in NFPanNET tumorigenesis suggests a key role for aberrant methylation in the pathogenesis of NFPanNETs.

Prognostic significance of Chromogranin A in small pancreatic neuroendocrine tumors

BACKGROUND

The incidence of nonfunctional pancreatic neuroendocrine tumors ≤2cm is rising. The biologic behavior of these tumors is variable; thus, their management remains controversial. Chromogranin A upregulation is a useful diagnostic biomarker of neuroendocrine tumors; however, the prognostic significance of Chromogranin A is unclear. The objective of this study was to determine whether Chromogranin A levels have prognostic value in pancreatic neuroendocrine tumor patients and may help guide management.

METHODS

We evaluated the National Cancer Database over a 10-year period (2004-2013). Patients with pancreatic neuroendocrine tumors measuring ≤2cm, without distant metastases, were identified and categorized as Chromogranin A high (>420ng/mL) or Chromogranin A low (≤420ng/mL), and those lacking data on Chromogranin A levels were excluded from the study. Univariate and multivariate analyses were performed using Cox proportional hazards model. Cut-point determination was performed using the Contal and O'Quigley method.

RESULTS

Of the 445 eligible patients, 352 (79%) were Chromogranin A low and 93 (21%) were Chromogranin A high. Median Chromogranin A level was 71ng/mL (interquartile range, 24-294ng/mL). Chromogranin levels were associated with clinical nodal status and grade. Furthermore, on multivariate analysis, Chromogranin A levels (Chromogranin A high versus Chromogranin A low) independently predicted overall survival after controlling for tumor size, grade, clinical nodal status, and academic status of the facility (hazard ratio: 7.90, 95%CI: 2.34-26.69, P = .001). The greatest benefit of surgical resection was noted in patients in the Chromogranin A high subgroup (log-rank P <.001).

CONCLUSION

Serum Chromogranin A levels can be incorporated in surgical decision-making for patients with small pancreatic neuroendocrine tumors. Patients in the Chromogranin A low group can be considered for observation, whereas patients in the Chromogranin A high group should be strongly considered for resection.

Pancreatic neuroendocrine tumor: review of heterogeneous spectrum of CT appearance

OBJECTIVE

Pancreatic neuroendocrine tumors (PanNETs) are uncommon pancreatic neoplasms and can be a diagnostic challenge with heterogeneous spectrum of CT appearance. We review CT findings of PanNETs and other mimics.

CONCLUSION

PanNETs are typically hypervascular and have avid enhancement on arterial and venous phase images. However, dedicated pancreas protocol may be needed due to their sometimes atypical appearance including transient enhancement. Careful evaluation of CT findings will help differentiate PanNETs from their mimics, and can be used to establish the diagnosis of a PanNETs. Although an accurate diagnosis can be based on serological, urine, and CT scan findings, confirmation is made via pathological examination.

Effect of Lanreotide Depot/Autogel on Urinary 5-Hydroxyindoleacetic Acid and Plasma Chromogranin A Biomarkers in Nonfunctional Metastatic Enteropancreatic Neuroendocrine Tumors

BACKGROUND

Urinary 5-hydroxyindoleacetic acid (5-HIAA) is an established biomarker in neuroendocrine tumors and carcinoid syndrome; however, its role in nonfunctional neuroendocrine tumors is not defined. We present post hoc data on urinary 5-HIAA and plasma chromogranin A (CgA) from the CLARINET study.

METHODS

Patients with well- or moderately differentiated, nonfunctioning, locally advanced or metastatic enteropancreatic neuroendocrine tumors were randomized to deep subcutaneous lanreotide depot/autogel 120 mg or placebo once every 28 days for 96 weeks. Tumor response, evaluated centrally (RECIST 1.0), and progression-free survival (PFS) were assessed by treatment and biochemical response, defined as (a) baseline >upper limit of normal (ULN, 41.6 μmol per day 5-HIAA; 98.1 μg/L CgA) and (b) ≥50% decrease from baseline and to ≤ULN value on study.

RESULTS

Forty-eight percent (82 of 171; lanreotide, n = 45; placebo, n = 37) and 66% (129 of 195; lanreotide, n = 65; placebo, n = 64) of randomized patients had 5-HIAA and CgA > ULN at baseline. Among patients with >ULN baseline values who did not progress after 96 weeks of treatment, significantly greater reductions in 5-HIAA and CgA were observed in lanreotide-treated versus placebo-treated patients throughout the study (all p < .05). PFS was significantly prolonged among 5-HIAA responders versus nonresponders (median not reached vs. 16.2 months, p < .0001; hazard ratio [HR] = 0.21, 95% confidence interval [CI], 0.09-0.48) and CgA responders versus nonresponders (median not reached vs. 16.2 months, p = .0070; HR = 0.30, 95% CI, 0.12-0.76), regardless of treatment arm. PFS was also significantly prolonged among lanreotide-treated 5-HIAA responders versus nonresponders (p = .0071) but was not significantly different among placebo-treated 5-HIAA responders versus nonresponders. There were no significant differences in PFS between lanreotide-treated CgA responders versus nonresponders or between placebo-treated CgA responders versus nonresponders.

CONCLUSIONS

The 5-HIAA findings are noteworthy because they occurred in patients with nonfunctioning enteropancreatic neuroendocrine tumors. Monitoring 5-HIAA and CgA may be useful when treating patients with nonfunctional neuroendocrine tumors.

IMPLICATIONS FOR PRACTICE

Current guidelines focus only on the monitoring of 5-hydroxyindoleacetic acid (5-HIAA) in the diagnosis and management of functional neuroendocrine tumors with carcinoid syndrome. The current post hoc analysis of patients with nonfunctional enteropancreatic neuroendocrine tumors in the CLARINET study demonstrated that measuring and following both 5-HIAA and chromogranin A as biomarkers of disease progression may be useful in the management of patients with nonfunctional neuroendocrine tumors.

Endoscopic ultrasound appearance of pancreatic serotonin-staining neuroendocrine neoplasms

BACKGROUND/OBJECTIVES

The pancreatic localization of serotonin-staining neuroendocrine neoplasms is extremely rare. This is a retrospective study aimed at analyzing the endoscopic ultrasound appearance of pancreatic serotoninoma.

METHODS

Between 2010 and 2016, all consecutive patients with histologically proven pancreatic serotoninoma who had undergone endoscopic ultrasound were enrolled.

RESULTS

Eight patients (six F, median age 68.5 years) had a diagnosis of pancreatic serotoninoma and underwent endoscopic ultrasound examinations. Median diameter of the lesion was ten mm. The nodule echotexture was hypoechoic in seven out of eight cases. The most frequent localization was the pancreatic neck (four); in three cases, the tumor was located in the pancreatic head and in one in the body. In seven cases the tumor caused a main pancreatic duct dilation; in three cases also the secondary ducts were dilated. In one case a dilation of the common bile duct was observed. At contrast-enhanced endoscopic ultrasound no one showed the typical contrast-enhancement. Elastography (available in two patients) showed a rigid pattern of the lesion.

CONCLUSIONS

From this case series a specific endoscopic ultrasound appearance resulted for pancreatic serotoninoma, different from other types of pancreatic neuroendocrine neoplasm, but it is difficult to differentiate it from a pancreatic adenocarcinoma or an intraductal papillary mucinous neoplasm.

Hepatic Resection for Non-functional Neuroendocrine Liver Metastasis: Does the Presence of Unresected Primary Tumor or Extrahepatic Metastatic Disease Matter?

OBJECTIVES

The objective of this study was to assess the impact of unresected primary tumor, as well as extrahepatic metastasis, on the long-term prognosis of patients undergoing hepatic resection for non-functional neuroendocrine liver metastasis (NF-NELM).

METHODS

Patients who underwent hepatic resection for NF-NELM were identified from a multi-institutional database. Data on clinical and pathological details, as well as the long-term overall survival (OS) were obtained and compared. Propensity score matching was performed to generate matched pairs of patients.

RESULTS

Among the 332 patients with NF-NELM, 281 (84.6%) underwent primary tumor resection, while 51 (15.4%) did not. Patients who underwent primary resection were more likely to have a pancreatic primary and metachronous NELM. The long-term OS of patients who did and did not have the primary neuroendocrine tumor (NET) resected was comparable on both unmatched (10-year survival rate 66.8% vs. 54.0%, p = 0.192) and matched (10-year survival rate 75.7% vs. 60.4%, p = 0.271) analyses. In contrast, patients with NF-NELM and extrahepatic metastasis had a worse OS following resection compared with patients who had intrahepatic-only metastasis on unmatched (10-year survival rate 37.5% vs. 69.3%, p = 0.002) and matched (10-year survival rate 37.5% vs. 86.3%, p = 0.011) analyses. On multivariable analysis, while resection of the primary NET was not associated with OS (hazard ratio [HR] 0.7, 95% confidence interval [CI] 0.4-1.2, p = 0.195), the presence of extrahepatic metastasis was independently associated with long-term risk of death (HR 3.9, 95% CI 1.7-9.2, p = 0.002).

CONCLUSIONS

While surgery should be considered for patients with NF-NELM who have an unresectable primary tumor, operative resection of NF-NELM may not be as beneficial in patients with extrahepatic disease.

Transcriptional alterations in hereditary and sporadic nonfunctioning pancreatic neuroendocrine tumors according to genotype

BACKGROUND

Nonfunctioning pancreatic neuroendocrine tumors (NFPanNETs) may be sporadic or inherited because of germline mutations associated with von Hippel-Lindau disease (VHL) or multiple endocrine neoplasia type 1 (MEN1). The clinical behavior of NFPanNETs is difficult to predict, even in tumors of the same stage and grade. The authors analyzed genotype-specific patterns of transcriptional messenger RNA (mRNA) levels of NFPanNETs to understand the molecular features that determine PanNET phenotype.

METHODS

Thirty-two samples were included for genome-wide mRNA gene expression analysis (9 VHL-associated, 10 MEN1-associated, and 9 sporadic NFPanNETs and 4 purified normal islet cell [NIC] samples). Validation of genes was performed by real-time polymerase chain reaction analysis and immunohistochemistry. Gene expression profiles were analyzed by tumor genotype, and pathway analysis was curated.

RESULTS

Consensus clustering of mRNA expression revealed separate clustering of NICs, VHL-associated NFPanNETs, and MEN1-associated NFPanNETs; whereas some sporadic tumors clustered with MEN1. Four of 5 MEN1-like sporadic PanNET subtypes had loss of heterozygosity at the MEN1 gene locus. Pathway analysis demonstrated subtype-specific pathway activation, comprising angiogenesis and immune response in VHL; neuronal development in MEN1; protein ubiquitination in the new MEN1/sporadic subtype; and cytokinesis and cilium/microtubule development in sporadic NFPanNETs. Among many genes, platelet-derived growth factor receptor β (PDGFRB), lymphoid enhancer-binding factor-1 (Lef-1), cyclin-dependent kinase 4 (CDK4), and CDK6 were upregulated in VHL or MEN1 NFPanNETs, providing potential subtype-specific treatment targets.

CONCLUSIONS

Distinct mRNA expression patterns were identified in sporadic-associated, VHL-associated, and MEN1-associated NFPanNETs. The current results uncover new pathways involved in NFPanNETs that are subtype-specific and provide potential new diagnostic or therapeutic targets based on tumor subtype. Cancer 2018;124:636-47. © 2017 American Cancer Society.

Carbohydrate antigen 19-9 as a prognostic biomarker in pancreatic neuroendocrine tumors

Carbohydrate antigen 19-9 (CA19-9) is not generally considered to be a biomarker in pancreatic neuroendocrine tumors (pNETs), as the majority of pNETs present with a normal range of CA19-9. The present study aimed to evaluate the role of serum CA19-9 levels as a prognostic factor in a relatively large number of patients with pNETs. Consecutive patients were retrospectively collected from a single institution between June 2006 and February 2015. The receiver operating characteristic (ROC) curve and the area under the ROC curve were used to select the cut-off values for the baseline CA19-9 levels. The primary end point was set as overall survival. Potential factors associated with the abnormal elevation of CA19-9 expression levels in pNETs were also investigated. The cut-off value for CA19-9 was 16 U/ml as determined by the ROC curve, and for the area under the ROC curve it was 0.68. In total, 32.7% of patients (51/156) had CA19-9 expression levels higher than the cut-off value. Univariate analysis demonstrated that CA19-9 >16 U/ml was an adverse prognostic factor for patients' overall survival. The CA19-9 >16 U/ml group had a statistically higher proportion of tumor node metastasis (TNM) stage III or IV, as compared with the CA19-9 ≤16 U/ml group. To the best of our knowledge, the present study is the first to demonstrate that CA19-9 is a prognostic biomarker of pNETs, one that may reflect its aggressiveness and severity.

Regional Metastatic Behavior of Nonfunctional Pancreatic Neuroendocrine Tumors: Impact of Lymph Node Positivity on Survival

OBJECTIVES

Literature addressing the significance of lymph node positivity in the management of nonfunctional pancreatic neuroendocrine tumors (PNETs) is conflicting.

METHODS

The National Cancer Data Base was queried for patients who underwent surgical resection of nonfunctional PNETs between 1998 and 2011. Clinical data and overall survival were analyzed using χ and Cox proportional hazards regression. Multiple imputation was used as a comparative analysis because of the high number of patients missing data on tumor grade.

RESULTS

Two thousand seven hundred thirty-five patients were identified. The overall incidence of lymph node metastasis was 51%. In the subset of patients with grade 1 tumors less than 1 cm, 24% had positive lymph nodes. Overall median survival for patients with negative lymph nodes was 11 years compared with 8 years for lymph node-positive patients (P < 0.001). On multivariate survival analysis, tumor grade, distant metastases, regional lymph node involvement, positive surgical margins, male sex, and older age were predictive of decreased overall survival.

CONCLUSIONS

Lymph node positivity was associated with decreased overall survival. The incidence of lymph node involvement in resected low-grade tumors less than 1 cm is higher than previously reported. Patients selected for resection of PNETs should be offered lymphadenectomy for staging.