Redefining the Ki-67 Index Stratification for Low-Grade Pancreatic Neuroendocrine Tumors: Improving Its Prognostic Value for Recurrence of Disease

A novel model for predicting postoperative liver metastasis in R0 resected pancreatic neuroendocrine tumors: integrating computational pathology and deep learning-radiomics

BACKGROUND

Postoperative liver metastasis significantly impacts the prognosis of pancreatic neuroendocrine tumor (panNET) patients after R0 resection. Combining computational pathology and deep learning radiomics can enhance the detection of postoperative liver metastasis in panNET patients.

METHODS

Clinical data, pathology slides, and radiographic images were collected from 163 panNET patients post-R0 resection at Fudan University Shanghai Cancer Center (FUSCC) and FUSCC Pathology Consultation Center. Digital image analysis and deep learning identified liver metastasis-related features in Ki67-stained whole slide images (WSIs) and enhanced CT scans to create a nomogram. The model's performance was validated in both internal and external test cohorts.

RESULTS

Multivariate logistic regression identified nerve infiltration as an independent risk factor for liver metastasis (p < 0.05). The Pathomics score, which was based on a hotspot and the heterogeneous distribution of Ki67 staining, showed improved predictive accuracy for liver metastasis (AUC = 0.799). The deep learning-radiomics (DLR) score achieved an AUC of 0.875. The integrated nomogram, which combines clinical, pathological, and imaging features, demonstrated outstanding performance, with an AUC of 0.985 in the training cohort and 0.961 in the validation cohort. High-risk group had a median recurrence-free survival of 28.5 months compared to 34.7 months for the low-risk group, showing significant correlation with prognosis (p < 0.05).

CONCLUSION

A new predictive model that integrates computational pathologic scores and deep learning-radiomics can better predict postoperative liver metastasis in panNET patients, aiding clinicians in developing personalized treatments.

Impact of Regional Metastasis on Survival for Patients with Nonfunctional Pancreatic Neuroendocrine Tumors: A Systematic Review

BACKGROUND

Controversy exists regarding the benefit of lymphadenectomy for nonfunctional pancreatic neuroendocrine tumors (NF-PNET).

PATIENTS AND METHODS

MEDLINE/PubMed, EMBASE, and the Cochrane Library were searched for studies of pancreatic neuroendocrine tumors (PNET) published between 1990 and 2021. Studies of functional PNET were excluded. Reported incidence of lymph node metastasis (LNM) and survival analysis of either disease-free survival (DFS) or overall survival (OS) were required for inclusion.

RESULTS

Overall, 52 studies analyzing 24,608 PNET met the inclusion criteria. The reported LNM rate for NF-PNET ranged from 7 to 64 % (median 24.5%). Reported LNM rates ranged from 7 to 51% (median 11%) for NF-PNET< 2 cm in 14 studies and 29-47% (median 38%) in NF-PNET > 2 cm. In total, 19 studies (66%) reported LNM to have a negative impact on DFS. Additionally, 21 studies (60%) reported LNM to have a negative impact on OS. Two studies investigating the impact of lymphadenectomy (LND) found LND had the greatest impact for large, high-grade tumors. The overall quality of available evidence was low as assessed by the Grading of Recommendations, Assessment, Development, and Evaluation System.

CONCLUSIONS

Published literature evaluating the impact of regional LNM and LND in PNET is confounded by heterogeneity in practice patterns and the retrospective nature of these cohort studies. Most studies suggest high rates of LNM in NF-PNET that negatively impact DFS and OS. Given the high rate of LNM in NF-PNET and its potential detrimental effect on DFS and OS, we recommend lymphadenectomy be completed for NF-PNET > 2 cm and strongly considered for NF-PNET < 2 cm.

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.

Total pancreatoduodenectomy for multiple pancreatic cysts in von Hippel-Lindau disease presenting as obstructive jaundice: A case report

INTRODUCTION

Von Hippel-Lindau (VHL) disease can be known as a rare autosomal dominant syndrome that affects some organ systems and is characterized by the growth of both benign and malignant tumors. Diagnosis and management of VHL were needed to have better outcomes.

CASE PRESENTATION

A 39-year-old male with a history of VHL disease and positive family history presented with jaundice and pruritus. He had a history of craniotomy thrice. Laboratory workup revealed elevated total bilirubin level with conjugated bilirubin predominant. The contrast-enhanced MRI showed dilatation of biliary tree with suspicion of partial obstruction by multiple cysts in the pancreas, with ±0.5-5 cm in diameter. A PET/CT scan showed multiple lesions corresponding to VHL disease. The patient underwent total pancreatoduodenectomy. The histopathology finding was multicystic pancreatic hamartoma with neuroendocrine cell hyperplasia.

CLINICAL DISCUSSION

Multiple pancreatic cysts without prior pancreatic inflammatory episodes should suggest VHL disease and prompt a genetic test, according to clinical presentation. As soon as the diagnosis is made, all potential family members must be screened, and those who are affected must receive genetic counseling and strict follow-up care to treat the disease's potentially fatal CNS and visceral manifestations. Total pancreatoduodenectomy was performed according to jaundice, risk of pancreas malignancy, and the existence of endocrine pancreatic insufficiency.

CONCLUSION

Total pancreatoduodenectomy could be performed to relieve the symptom severity and avoid the possibility of malignant changes in VHL.

Clinical Prediction Models for Recurrence in Patients with Resectable Grade 1 and 2 Sporadic Non-Functional Pancreatic Neuroendocrine Tumors: A Systematic Review

Recurrence after resection in patients with non-functional pancreatic neuroendocrine tumors (NF-pNET) has a considerable impact on overall survival. Accurate risk stratification will tailor optimal follow-up strategies. This systematic review assessed available prediction models, including their quality. This systematic review followed PRISMA and CHARMS guidelines. PubMed, Embase, and the Cochrane Library were searched up to December 2022 for studies that developed, updated, or validated prediction models for recurrence in resectable grade 1 or 2 NF-pNET. Studies were critically appraised. After screening 1883 studies, 14 studies with 3583 patients were included: 13 original prediction models and 1 prediction model validation. Four models were developed for preoperative and nine for postoperative use. Six models were presented as scoring systems, five as nomograms, and two as staging systems. The c statistic ranged from 0.67 to 0.94. The most frequently included predictors were tumor grade, tumor size, and lymph node positivity. Critical appraisal deemed all development studies as having a high risk of bias and the validation study as having a low risk of bias. This systematic review identified 13 prediction models for recurrence in resectable NF-pNET with external validations for 3 of them. External validation of prediction models improves their reliability and stimulates use in daily practice.

Venous invasion and lymphatic invasion are correlated with the postoperative prognosis of pancreatic neuroendocrine neoplasm

BACKGROUND

To determine treatment strategies corresponding to a wide range of pancreatic neuroendocrine neoplasms staging, easier-to-use and detailed prognostic classification is required.

METHODS

Patients with pancreatic neuroendocrine neoplasms who underwent curative-intent surgery at the University of Tokyo Hospital between 2000 and 2018 were retrospectively reviewed. The presence or absence of venous and lymphatic invasion was assessed. Multivariable analysis was performed to identify the risk factors of shorter overall survival and recurrence-free survival. Patients were classified into the following 3 groups: a lymphovascular invasion 0 group, whereby both venous and lymphatic invasion were negative; an lymphovascular invasion 1 group, where either of the 2 was positive; and an lymphovascular invasion 2 group, where both were positive. The survival curves and recurrence patterns of the 3 groups were compared.

RESULTS

Eighty-nine patients were analyzed. Multivariable analysis revealed that lymphatic invasion and Ki-67 index (≥ 3.0%) were independent prognostic factors of recurrence-free survival (hazard ratio: 5.2 and 3.6). Fifty-three patients were classified as lymphovascular invasion 0, 26 as lymphovascular invasion 1, and 10 as lymphovascular invasion 2. The recurrence-free survival curves of the 3 groups were significantly stratified (10-year recurrence-free survival: 89.1% in lymphovascular invasion 0, 57.1% in lymphovascular invasion 1, and 18.3% in lymphovascular invasion 2). Five-year cumulative liver and lymph node metastasis of lymphovascular invasion 0, lymphovascular invasion 1, and lymphovascular invasion 2 were well stratified at 0% and 3.8%, 15.8% and 23.1%, and 33.3% and 70.0%, respectively.

CONCLUSION

Postoperative prognosis of resected pancreatic neuroendocrine neoplasms could be finely classified by venous invasion and lymphatic invasion. Management after curative-intent surgery for pancreatic neuroendocrine neoplasms may be changed by this new classification.

Perspectives on the diagnostic, predictive and prognostic markers of neuroendocrine neoplasms (Review)

Neuroendocrine neoplasms (NENs) are a heterogeneous group of rare tumors with different types of physiology and prognosis. Therefore, prognostic information, including morphological differentiation, grade, tumor stage and primary location, are invaluable and contribute to the formulation of treatment decisions. Biomarkers that are currently used, including chromogranin A (CgA), serotonin and neuron-specific enolase, are singular parameters that cannot be used to accurately predict variables associated with tumor growth, including proliferation, metabolic rate and metastatic potential. In addition, site-specific biomarkers, such as insulin and gastrin, cannot be applied to all types of NENs. The clinical application of broad-spectrum markers, as it is the case for CgA, remains controversial despite being widely used. Due to limitations of the currently available mono-analyte biomarkers, recent studies were conducted to explore novel parameters for NEN diagnosis, prognosis, therapy stratification and evaluation of treatment response. Identification of prognostic factors for predicting NEN outcome is a critical requirement for the planning of adequate clinical management. Advances in ‘liquid’ biopsies and genomic analysis techniques, including microRNA, circulating tumor DNA or circulating tumor cells and sophisticated biomathematical analysis techniques, such as NETest or molecular image-based biomarkers, are currently under investigation as potentially novel tools for the management of NENs in the future. Despite these recent findings yielding promising observations, further research is necessary. The present review therefore summarizes the existing knowledge and recent advancements in the exploration of biochemical markers for NENs, with focus on gastroenteropancreatic-neuroendocrine tumors.

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.

The Clinical Significance of Lymph Node Ratio and Ki-67 Expression in Papillary Thyroid Cancer

BACKGROUND

The N stage in papillary thyroid cancer (PTC) is an important prognostic factor based on anatomical localization of cervical lymph nodes (LNs) only and not the extent of lymphatic metastasis. In this retrospective study, the clinical significance of lymph node ratio (LNR) and tumor cell proliferation in relation to the conventional classification of PTC was explored.

METHODS

Patients diagnosed with PTC at the Karolinska University Hospital in Stockholm, Sweden, during the years 2009-2011 were included. The LNR, defined as the number of metastatic LNs divided by the total number of LNs investigated, and the Ki-67 index were analyzed in relation to clinical data.

RESULTS

The median number of LN removed was 16 with the following N stage distribution: N0 (26%), N1a (45%), and N1b (29%). A Ki-67 index of ≥3% was significantly correlated with the presence of metastases and tumor recurrence with a sensitivity of 50% and specificity of 80% (p = 0.015). Lymph node ratio ≥21% was related to tumor recurrence with sensitivity of 89% and specificity of 70% (p = 0.006). Patients with LN metastases in the lateral cervical compartment only had significantly lower LNR (14.5%) compared to those with both central and lateral cervical metastases (39.5%) (p = 0.004) and exhibited no tumor recurrence. Increased Ki-67 index was significantly related to LNR ≥21% (p = 0.023) but was not associated with N stage.

CONCLUSIONS

The Ki-67 proliferation index and LNR may better reflect the malignant behavior of PTC compared to the anatomical classification of LN metastases solely.

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.

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.

Pancreatic neuroendocrine neoplasms: current state and ongoing controversies on terminology, classification and prognostication

Significant improvements have taken place in our understanding of classification neuroendocrine neoplasms of the pancreas in the past decade. These are now regarded in three entirely separate categories: (I) neuroendocrine tumors (PanNETs) are by definition well differentiated, the pancreatic counterpart of carcinoids; (II) neuroendocrine carcinomas, which are poorly differentiated (PDNEC), the pancreatic examples of small cell carcinomas or large cell neuroendocrine carcinomas; (III) other neoplasms that have neuroendocrine differentiation or a distinct neuroendocrine component. PanNETs are by far the most common. They are now regarded as malignancies (albeit often curable when low grade and low stage) with the exception of minute incidental proliferations (tumorlets, or dysplastic-like changes) seen in the setting of some syndromes like MEN. PanNETs are staged based on their size, and for small T1 tumors, watchful waiting is now being considered, although these tumors are also known to show about 10% metastatic rate and/or progression, creating concerns about this approach. PanNETs are graded into 3, based on the proliferative activity, mostly based on the Ki-67 index, and also partly mitotic activity, although the latter seldom if ever is the determinant of the final grade. Neuroendocrine neoplasms with well differentiated morphology but Ki-67 >20% are now regarded as PanNET Grade 3 (G3); they have been shown to have a prognosis significantly worse than lesser grade PanNETs but still incomparably better than frank PDNECs, the latter typically has Ki-67 >50% (often much higher) and require platinum-based chemotherapy. There are also cases that are ambiguous between PanNET-G3 and PDNEC, and very rarely transformation of the former to the latter appears to occur. For low grade (G1/G2) PanNETs, more refined criteria to further prognosticate this group are needed. Morphologic variants being recognized may bring new perspectives to this group.

Prognostic factors for the outcome of nonfunctioning pancreatic neuroendocrine tumors in MEN1: a systematic review of literature

Metastatic duodenopancreatic neuro-endocrine tumors (dpNETs) are the most important disease-related cause of death in patients with multiple endocrine neoplasia type 1 (MEN1). Nonfunctioning pNETs (NF-pNETs) are highly prevalent in MEN1 and clinically heterogeneous. Therefore, management is controversial. Data on prognostic factors for risk stratification are limited. This systematic review aims to establish the current state of evidence regarding prognostic factors in MEN1-related NF-pNETs. We systematically searched four databases for studies assessing prognostic value of any factor on NF-pNET progression, development of distant metastases, and/or overall survival. In- and exclusion, critical appraisal and data-extraction were performed independently by two authors according to pre-defined criteria. Thirteen studies (370 unique patients) were included. Prognostic factors investigated were tumor size, timing of surgical resection, WHO grade, methylation, p27/p18 expression by immunohistochemistry (IHC), ARX/PDX1 IHC and alternative lengthening of telomeres. Results were complemented with evidence from studies in MEN1-related pNET for which data could not be separately extracted for NF-pNET and data from sporadic NF-pNET. We found that the most important prognostic factors used in clinical decision making in MEN1-related NF-pNETs are tumor size and grade. NF-pNETs <2 cm may be managed with watchful waiting, while surgical resection is advised for NF-pNETs ≥2 cm. Grade 2 NF-pNETs should be considered high risk. The most promising and MEN1-relevant avenues of prognostic research are multi-analyte circulating biomarkers, tissue-based molecular factors and imaging-based prognostication. Multi-institutional collaboration between clinical, translation and basic scientists with uniform data and biospecimen collection in prospective cohorts should advance the field.

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

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

Multi-institutional Development and External Validation of a Nomogram to Predict Recurrence After Curative Resection of Pancreatic Neuroendocrine Tumors

OBJECTIVE

To develop a nomogram estimating the probability of recurrence free at 5 years after resection for localized grade 1 (G1)/ grade 2 (G2) pancreatic neuroendocrine tumors (PanNETs).

BACKGROUND

Among patients undergoing resection of PanNETs, approximately 17% experience recurrence. It is not established which patients are at risk, with no consensus on optimal follow-up.

METHOD

A multi-institutional database of patients with G1/G2 PanNETs treated at 2 institutions was used to develop a nomogram estimating the rate of freedom from recurrence at 5 years after curative resection. A second cohort of patients from 3 additional institutions was used to validate the nomogram. Prognostic factors were assessed by univariate analysis using Cox regression model. The nomogram was internally validated using bootstrap resampling method and on the external cohort. Performance was assessed by concordance index (c-index) and a calibration curve.

RESULTS

The nomogram was constructed using a cohort of 632 patients. Overall, 68% of PanNETs were G1, the median follow-up was 51 months, and we observed 74 recurrences. Variables included in the nomogram were the number of positive nodes, tumor diameter, Ki-67, and vascular/perineural invasion. The model bias-corrected c-index from the internal validation was 0.85, which was higher than European Neuroendocrine Tumors Society/American Joint Committee on Cancer 8th staging scheme (c-index 0.76, P = <0.001). On the external cohort of 328 patients, the nomogram c-index was 0.84 (95% confidence interval 0.79-0.88).

CONCLUSION

Our externally validated nomogram predicts the probability of recurrence-free survival at 5 years after PanNETs curative resection, with improved accuracy over current staging systems. Estimating individual recurrence risk will guide the development of personalized surveillance programs after surgery.

A Novel Validated Recurrence Risk Score to Guide a Pragmatic Surveillance Strategy After Resection of Pancreatic Neuroendocrine Tumors: An International Study of 1006 Patients

OBJECTIVE

Despite heterogeneous biology, similar surveillance schemas are utilized after resection of all pancreatic neuroendocrine tumors (PanNETs). Given concerns regarding excess radiation exposure and financial burden, our aim was to develop a prognostic score for disease recurrence to guide individually tailored surveillance strategies.

METHODS

All patients with primary nonfunctioning, nonmetastatic well/moderately differentiated PanNETs who underwent curative-intent resection at 9-institutions from 2000 to 2016 were included (n = 1006). A Recurrence Risk Score (RRS) was developed from a randomly selected derivation cohort comprised of 67% of patients and verified on the validation-cohort comprised of the remaining 33%.

RESULTS

On multivariable analysis, patients within the derivation cohort (n = 681) with symptomatic tumors (jaundice, pain, bleeding), tumors >2 cm, Ki67 >3%, and lymph node (LN) (+) disease had increased recurrence. Each factor was assigned a score based on their weighted odds ratio that formed a RRS of 0 to 10: symptomatic = 1, tumor >2 cm = 2, Ki67 3% to 20% = 1, Ki67 >20% = 6, LN (+) = 1. Patients were grouped into low- (RRS = 0-2; n = 247), intermediate-(RRS = 3-5; n = 204), or high (RRS = 6-10; n = 9)-risk groups. At 24 months, 33% of high RRS recurred, whereas only 2% of low and 14% of intermediate RRS recurred. This persisted in the validation cohort (n = 325).

CONCLUSIONS

This international, novel, internally validated RRS accurately stratifies recurrence-free survival for patients with resected PanNETs. Given their unique recurrence patterns, surveillance intervals of 12, 6, and 3 months are proposed for low, intermediate, and high RRS patients, respectively, to minimize radiation exposure and optimize cost/resource utilization.