Risk factors for short recurrence-free survival after resection of pancreatic neuroendocrine tumor (PanNET) liver metastases: which patients should undergo resection?

Distinct clinicopathological features of neuroendocrine liver metastases originating from the pancreas and rectum

INTRODUCTION

Survival comparisons among patients with liver metastases from pancreatic and rectal neuroendocrine tumors (NETs) were limited, and the efficacy of observation rules in patients undergoing hepatectomy for neuroendocrine liver metastases (NELMs) was unknown. This study aims to distinguish these characteristics and clarify the effects of the observation rules on NELMs.

METHODS

Clinical data were separately collected from patients with pancreatic and rectal NELMs at medical centers in both Japan and China. The Japanese cohort followed the observation rules for the resection of NELMs. A comparative analysis was conducted on clinical characteristics and prognosis features such as overall survival time (OS) and disease-free survival interval (DFS-I).

RESULTS

Enrollment included 47 and 34 patients from Japan and China, respectively. Of these, 69 and 12 patients had tumors originating from the pancreas and rectum, respectively. The OS time in patients undergoing primary tumor resection was significantly longer; however, the OS time between the patients undergoing and not undergoing radical resection of liver metastasis was the same. In asynchronous NELMs, patients with rectal (R)-NELMs showed a significantly higher proportion of type III NELMs. Additionally, the median DFS-I of asynchronous R-NELMs was longer than the recommended follow-up time, with 71.4% of them classified as G2. In the Japanese cohort, patients who adhered to the observation rules exhibited a longer median DFS after hepatectomy for NELMs compared with their counterparts.

CONCLUSION

Although curative surgery is crucial for primary lesions, personalized approaches are required to manage NELMs. Extended overall follow-ups and shortened follow-up intervals are recommended for G2 stage rectal NETs. The observation rules for NELMs require further validation with a larger sample size.

Two machine learning-based nomogram to predict risk and prognostic factors for liver metastasis from pancreatic neuroendocrine tumors: a multicenter study

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are one of the most common endocrine tumors, and liver metastasis (LMs) are the most common location of metastasis from PNETS; However, there is no valid nomogram to predict the diagnosis and prognosis of liver metastasis (LMs) from PNETs. Therefore, we aimed to develop a valid predictive model to aid physicians in making better clinical decisions.

METHODS

We screened patients in the Surveillance, Epidemiology, and End Results (SEER) database from 2010-2016. Feature selection was performed by machine learning algorithms and then models were constructed. Two nomograms were constructed based on the feature selection algorithm to predict the prognosis and risk of LMs from PNETs. We then used the area under the curve (AUC), receiver operating characteristic (ROC) curve, calibration plot and consistency index (C-index) to evaluate the discrimination and accuracy of the nomograms. Kaplan-Meier (K-M) survival curves and decision curve analysis (DCA) were also used further to validate the clinical efficacy of the nomograms. In the external validation set, the same validation is performed.

RESULTS

Of the 1998 patients screened from the SEER database with a pathological diagnosis of PNET, 343 (17.2%) had LMs at the time of diagnosis. The independent risk factors for the occurrence of LMs in PNET patients included histological grade, N stage, surgery, chemotherapy, tumor size and bone metastasis. According to Cox regression analysis, we found that histological subtype, histological grade, surgery, age, and brain metastasis were independent prognostic factors for PNET patients with LMs. Based on these factors, the two nomograms demonstrated good performance in model evaluation.

CONCLUSION

We developed two clinically significant predictive models to aid physicians in personalized clinical decision-makings.

Preoperative risk stratification of lymph node metastasis for non-functional pancreatic neuroendocrine neoplasm: An international dual-institutional study

BACKGROUND

/Objectives: Although the presence of lymph node metastasis (LNM) defines malignant potential, preoperative prediction of LNM has not been established for non-functional pancreatic neuroendocrine neoplasm (NF-PNEN). We sought to develop a prediction system using only preoperatively available factors that would stratify the risk of LNM for NF-PNEN.

METHODS

We retrospectively reviewed patients who underwent R0/1 resection of NF-PNEN at Kyoto University (2007-2019) and the University of California, San Francisco (2010-2019). Risk stratification of LNM was developed using preoperative factors by the logistic regression analysis. Long-term outcomes were compared across the risk groups.

RESULTS

A total of 131 patients were included in this study. Lymph nodes were pathologically examined in 116 patients, 23 (20%) of whom had LNM. Radiological tumor size [1.5-3.5 cm (odds ratio: 13.5, 95% confidence interval: 1.77-398) and >3.5 cm (72.4, 9.06-2257) against ≤1.5 cm], <50% cystic component (8.46 × 10^6, 1.68 × 10^106-), and dilatation of main pancreatic duct ≥5 mm (31.2, 3.94-702) were independently associated with LNM. When patients were classified as the low-risk (43 patients), intermediate-risk (44 patients), and high-risk groups (29 patients), proportions of LNM differed significantly across the groups (0%, 14%, and 59%, respectively). Recurrence-free survival (RFS) of the low- and intermediate-risk groups were significantly better than that of the high-risk group (5-year RFS rates of 92.2%, 85.4%, and 47.1%, respectively).

CONCLUSIONS

The prediction system using preoperative radiological factors stratifies the risk of LNM for NF-PNEN. This stratification helps to predict malignant potential and determine the surgical procedure and necessity of regional lymphadenectomy.

Tumour grade and primary site predict patterns of recurrence and survival in patients with resected gastroenteropancreatic neuroendocrine tumors

BACKGROUND

Patterns of recurrence help to inform surveillance of patients with resected gastroenteropancreatic neuroendocrine tumors (GEP-NETs).

METHODS

Patients with GEP-NETs in British Columbia, Canada (2004-2015) were reviewed. Associations between tumor characteristics, recurrence and survival were analyzed.

RESULTS

Among 759 patients, 41%, 25%, and 17% had grade 1, 2, and 3 disease, respectively. 387 patients had R0/R1 resections, of which 30% recurred (median 25 months). 5-year incidence of recurrence was 22% (grade 1), 46% (grade 2), and 59% (grade 3) (p < 0.001). Grade predicted distant recurrence (Grade 2 HR 1.89, 95% CI 1.16-3.07; p = 0.011; Grade 3 HR 3.29, 95% CI 1.81-5.99; p < 0.001). Compared to small bowel NETs, pancreas NETs had less peritoneal recurrence (OR 0.15, 95% CI 0.03-0.68, p = 0.014). No patients had isolated pulmonary recurrences.

CONCLUSION

Higher grade tumors and pancreatic NETs require more frequent surveillance. Evidence is limited for pulmonary surveillance.

Currently available treatment options for neuroendocrine liver metastases

Neuroendocrine neoplasms (NEN) are frequently characterized by a high propensity for metastasis to the liver, which appears to be a dominant site of distant-stage disease, affecting quality of life and overall survival. Liver surgery with the intention to cure is the treatment of choice for resectable neuroendocrine liver metastases (NELM), aiming to potentially prolong survival and ameliorate hormonal symptoms refractory to medical control. Surgical resection is indicated for patients with NELM from well-differentiated NEN, while its feasibility and complexity are largely dictated by the degree of liver involvement. As a result of advances in surgical techniques over the past decades, complex 1- and 2-stage, or repeat liver resections are performed safely and effectively by experienced surgeons. Furthermore, liver transplantation for the treatment of NELM should be anchored in a multimodal and multidisciplinary therapeutic strategy and restricted only to highly selected individual cases. A broad spectrum of interventional radiology treatments for NELM have recently been available, with expanding indications that are more applicable, as they are less limited by patient- and tumor-related parameters, being therefore important adjuncts or alternatives to surgery. Overall, liver-targeted treatment modalities may precede the administration of systemic molecular targeted agents and chemotherapy for patients with liver-dominant metastatic disease; these appear to be a crucial component of multimodal management of patients with NEN. In the present review, we discuss surgical and non-surgical liver-targeted treatment approaches for NELM, each complementing the other, with a view to assisting physicians in optimizing multimodal NEN patient care.

Case Report: Pancreatic Neuroendocrine Tumor With Liver Metastasis and Portal Vein Thrombosis

INTRODUCTION

Pancreatic neuroendocrine neoplasms (PNENs) are rare pancreatic tumors originating from pancreatic neuroendocrine cells. There is no consensus on the treatment for PNENs with unresectable liver metastases. Transcatheter arterial chemoembolization (TACE) is the preferred treatment for unresectable primary liver cancer. But the efficacy of TACE and anticoagulation in PNENs with unresectable liver metastases and portal vein thrombosis has never been reported.

METHODS AND RESULTS

We present the case of a 50-year-old male patient with hepatitis C who was found to have a single liver mass during a regular physical examination in 2016. The liver mass was surgically removed. Postoperative pathology suggested a neuroendocrine tumor of the liver, and it was suggested to look for the primary tumor. The patient was followed up until 2020, and the primary pancreatic tumor was found, along with multiple liver metastases and portal vein thrombosis. After transcatheter arterial embolization, anticoagulation, and endocrine therapy, the patient's tumor load was relieved, and the portal vein was recanalized.

CONCLUSION

The article reports the disease course in a case of a functional pancreatic neuroendocrine tumor with liver metastasis and portal vein thrombosis and reviews previous literature. To our knowledge, we reported for the first time the efficacy of TACE and anticoagulation in PNENs with unresectable liver metastases and portal vein thrombosis.