Adjunctive radiofrequency ablation of metastatic neuroendocrine cancer to the liver complements surgical resection

Liver-Directed Locoregional Therapies for Neuroendocrine Liver Metastases: Recent Advances and Management

Neuroendocrine tumors (NETs) are a heterogeneous class of cancers, predominately occurring in the gastroenteropancreatic system, which pose a growing health concern with a significant rise in incidence over the past four decades. Emerging from neuroendocrine cells, these tumors often elicit paraneoplastic syndromes such as carcinoid syndrome, which can manifest as a constellation of symptoms significantly impacting patients' quality of life. The prognosis of NETs is influenced by their tendency for metastasis, especially in cases involving the liver, where the estimated 5-year survival is between 20 and 40%. Although surgical resection remains the preferred curative option, challenges emerge in cases of neuroendocrine tumors with liver metastasis (NELM) with multifocal lobar involvement, and many patients may not meet the criteria for surgery. Thus, minimally invasive and non-surgical treatments, such as locoregional therapies, have surfaced. Overall, these approaches aim to prioritize symptom relief and aid in overall tumor control. This review examines locoregional therapies, encompassing catheter-driven procedures, ablative techniques, and radioembolization therapies. These interventions play a pivotal role in enhancing progression-free survival and managing hormonal symptoms, contributing to the dynamic landscape of evolving NELM treatment. This review meticulously explores each modality, presenting the current state of the literature on their utilization and efficacy in addressing NELM.

Liver Imaging in Gastroenteropancreatic Neuroendocrine Neoplasms

ABSTRACT

The incidence of neuroendocrine neoplasms (NENs) has gradually increased over the past few decades with the majority of patients presenting with metastases on initial presentation. The liver is the most common site of initial metastatic disease, and the presence of liver metastasis is an independent prognostic factor associated with a negative outcome. Because NENs are heterogenous neoplasms with variable differentiation, grading, and risk of grade transformation over time, accurate diagnosis and management of neuroendocrine liver lesions are both important and challenging. This is particularly so with the multiple liver-directed treatment options available. In this review article, we discuss the diagnosis, treatment, and response evaluation of NEN liver metastases.

Technical and Clinical Outcomes of Laparoscopic-Laparotomic Hepatocellular Carcinoma Thermal Ablation with Microwave Technology: Case Series and Review of Literature

PURPOSE

To evaluate technical and clinical outcomes of intraoperative (laparoscopic/laparotomic) microwave ablation on HCC.

MATERIALS AND METHODS

This is a retrospective single-center study evaluating consecutive patients treated for very early/early-stage HCC with intraoperative microwave ablation from 1 July 2017 to 30 June 2023. In these patients, a percutaneous US-guided approach was excluded due to the nodule's suboptimal visibility or harmful location and liver resection for a deep position or adherences. Data about the clinical stage, surgical approach, liver pathology and nodules characteristics, technical success, complications, and follow-up were collected. Technical success was intended as the absence of locoregional persistence at follow-up CT/MRI controls.

RESULTS

A total of 36 cirrhotic patients (M:F = 30:6, median age 67 years) were enrolled; 18/36 (50%) had a single nodule, 13/36 (36%) had two, 4/36 had three (11%), and 1/36 had four (3%). Among the patients, 24 (67%) were treated with laparoscopy, and 12/36 (33%) with a laparotomic approach. Sixty HCCs of 16.5 mm (6-50 mm) were treated for 7 min (2-30 min) with 100 W of power. A total of 55 nodules (92%) were treated successfully and showed no residual enhancement at the first postoperative follow-up; the other 5/60 (8%) underwent chemo/radioembolization. There was one complication (3%): a biliary fistula treated with percutaneous drainage and glue embolization. The average hospital stay was 3.5 days (1-51 days), and patients were followed up on average for 238 days (13-1792 days). During follow-up, 5/36 patients (14%) underwent liver transplantation, 1/36 (2%) died during hospitalization and 1 after discharge.

CONCLUSIONS

Laparoscopic/laparotomic intraoperative HCC MW ablation is feasible in patients unsuitable for percutaneous approach or hepatic resection, with rare complications and with good technical and clinical outcomes.

Neuroendocrine Tumors: Genomics and Molecular Biomarkers with a Focus on Metastatic Disease

Neuroendocrine tumors (NETs) are considered rare tumors that originate from specialized endocrine cells. Patients often present with metastatic disease at the time of diagnosis, which negatively impacts their quality of life and overall survival. An understanding of the genetic mutations that drive these tumors and the biomarkers used to detect new NET cases is important to identify patients at an earlier disease stage. Elevations in CgA, synaptophysin, and 5-HIAA are most commonly used to identify NETs and assess prognosis; however, new advances in whole genome sequencing and multigenomic blood assays have allowed for a greater understanding of the drivers of NETs and more sensitive and specific tests to diagnose tumors and assess disease response. Treating NET liver metastases is important in managing hormonal or carcinoid symptoms and is imperative to improve patient survival. Treatment for liver-dominant disease is varied; delineating biomarkers that may predict response will allow for better patient stratification.

Defining a New Classification System for the Surgical Management of Neuroendocrine Tumor Liver Metastases

Although rarely curative, hepatic cytoreduction of neuroendocrine tumor liver metastases (NETLM) is associated with improved symptom control and prolonged survival. Preoperative 68Ga DOTATATE and gadoxetic acid-enhanced liver MRI can improve characterization of hepatic disease extent to improve surgical clearance, and resection of the primary tumor is associated with improved survival regardless of whether the liver metastases are treated. As parenchymal-sparing surgical techniques and the lowering of the debulking threshold have expanded the numbers of eligible NETLM patients for hepatic cytoreduction, we propose a new classification system to help guide surgical management. A multimodal approach that includes surgery, liver-directed therapies, and systemic therapies has improved outcomes and increased longevity for patients with well-differentiated metastatic NET.

Reliability of Stereotactic Radiofrequency Ablation (SRFA) for Malignant Liver Tumors: Novice versus Experienced Operators

PURPOSE

To compare the results of a novice with those of experienced interventional radiologists (IRs) for stereotactic radiofrequency ablation (SRFA) of malignant liver tumors in terms of safety, technical success, and local tumor control.

METHODS

A database, including all SRFA procedures performed in a single center between January 2011 and December 2018 was retrospectively analyzed. A total of 39 ablation sessions performed by a novice IR were compared to the results of three more experienced IRs. Comparative SRFA sessions were selected using propensity score matching considering tumor type, age, sex, tumor size, and tumor number as matching variables. Overall, 549 target tumors were treated in 273 sessions. Median tumor size was 2.2 cm (1.0-8.5 cm) for 178 hepatocellular carcinomas (HCCs) and 3.0 cm (0.5-13.0 cm) for 371 metastases. A median of 2 (1-11) tumors were treated per session.

RESULTS

No significant differences were observed when comparing the results of more experienced IRs with those of a novice IR regarding the rates of major complications (6.8% [16/234] vs. 5.1% [2/39]; p = 0.477), mortality (1.3% [2/234] vs. 0% [0/39]; p = 0.690), primary technical efficacy (98.5% [525/533] vs. 98.9% [94/95]; p = 0.735), and local recurrence (5.6% [30/533] vs. 5.3% [5/95]; p = 0.886). However, the median planning/placement time was significantly shorter for the experienced IRs (92 min vs. 119 min; p = 0.002).

CONCLUSIONS

SRFA is a safe, effective, and reliable treatment option for malignant liver tumors and favorable outcomes can be achieved even by inexperienced operators with minimal supervision.

Systemic Therapy of Advanced Well-differentiated Small Bowel Neuroendocrine Tumors Progressive on Somatostatin Analogues

OPINION STATEMENT

Neuroendocrine neoplasms (NENs) are a heterogeneous group of tumors whose management requires a nuanced and multi-disciplinary approach in order to control symptoms, halt tumor growth, and improve survival outcomes. Of late, the treatment landscape of NENs has advanced considerably as a result of several pivotal clinical trials, which have established somatostatin analogues as first-line therapy for advanced, metastatic, well-differentiated neuroendocrine tumors (NETs). However, an evolving classification system as well as an increased understanding of distinct clinical, molecular, and biologic features contribute to complexity in management. In particular, there remains limited randomized prospective data in the somatostatin analogue (SSA)-refractory setting for patients with primary tumors that originate in the small bowel. For well-differentiated small bowel neuroendocrine tumors (SBNETs), treatment beyond SSAs includes radionuclide therapy, targeted agents, liver-directed therapy, and to a lesser extent, cytotoxic chemotherapy. In the current era, selection of these agents is largely based on expert opinion in the context of patient and tumor characteristics without definitive data on the preferred order of agents to administer. In this review, we aim to describe the treatment landscape of metastatic SBNETs beyond SSAs and provide an overview of novel treatments which are currently under clinical evaluation.

[Importance of surgery in distant metastatic pancreatic neuroendocrine neoplasms]

The majority of patients with pancreatic neuroendocrine neoplasms (pNEN) already present with distant metastases at diagnosis. The heterogeneity of pNEN and the broad spectrum of treatment options make adequate patient selection and an evidence-based strategy essential. In metastatic pNEN both primary resection and resection of liver metastases have been shown to improve overall survival. Surgical treatment of liver metastases can also be carried out with palliative intent, especially for symptomatic pNEN and can have a positive effect on disease-free survival and overall survival. Classical hepatectomy techniques and innovative techniques (two-stage resections, liver transplantation) are available to the surgeon. In complex growth types of liver metastases, there is increasing evidence for a combination of surgery and ablative methods. Due to a relevant risk of recurrence following liver resection, pNEN patients need to be included in multimodal treatment concepts. Current areas of interest in the treatment of metastatic pNEN are the use of adjuvant/neoadjuvant chemotherapy and surgery in G3-NEN and G3-NEC patients. The aim of this review is to give an overview on the impact of surgery in the situation of distant metastatic NEN of the pancreas.

Technical efficacy and local recurrence after stereotactic radiofrequency ablation of 2653 liver tumors: a 15-year single-center experience with evaluation of prognostic factors

PURPOSE

To assess the technical outcome and local tumor control of multi-probe stereotactic radiofrequency ablation (SRFA) in a large series of patients. Furthermore, to determine factors accounting for adverse outcomes.

MATERIAL AND METHODS

Between 2003 and 2018, 865 patients were treated by SRFA for 2653 primary and metastatic liver tumors with a median tumor size of 2.0 cm (0.5 - 19 cm). Primary technical efficacy (PTE) and local recurrence (LR) were evaluated, and possible predictors for adverse events analyzed using uni- and multi-variable binary logistic regression.

RESULTS

Overall, 2553 of 2653 tumors were successfully ablated at initial SRFA resulting in a PTE rate of 96.2%. Predictors of lower PTE rates were age > 70 years, tumor size > 5 cm, number of probes, location close to liver capsule/organs and segment II. LR occurred in 220 of 2653 tumors (8.3%) with the following predictors: age, tumor type/size, conglomerates, segments I/IVa/IVb, number of probes and location close to major vessels/bile duct. Multivariable analysis revealed tumor size > 5 cm (odds ratio [OR] 3.153), age > 70 years (OR 1.559), and location in segment II (OR 1.772) as independent prognostic factors for PTE, whereas tumor location close to major vessels (OR 1.653) and in segment IVb (OR 2.656) were identified as independent prognostic factors of LR.

CONCLUSIONS

Stereotactic RFA is an attractive option in the management of primary or metastatic liver tumors with good local tumor control, even in large tumors. The presented prognostic factors for adverse local oncological outcome might help to stratify unfavorable tumors for ablation.

Metastatic disease to the liver: Locoregional therapy strategies and outcomes

Secondary cancers of the liver are more than twenty times more common than primary tumors and are incurable in most cases. While surgical resection and systemic chemotherapy are often the first-line therapy for metastatic liver disease, a majority of patients present with bilobar disease not amenable to curative local resection. Furthermore, by the time metastasis to the liver has developed, many tumors demonstrate a degree of resistance to systemic chemotherapy. Fortunately, catheter-directed and percutaneous locoregional approaches have evolved as major treatment modalities for unresectable metastatic disease. These novel techniques can be used for diverse applications ranging from curative intent for small localized tumors, downstaging of large tumors for resection, or locoregional control and palliation of advanced disease. Their use has been associated with increased tumor response, increased disease-free and overall survival, and decreased morbidity and mortality in a broad range of metastatic disease. This review explores recent advances in liver-directed therapies for metastatic liver disease from primary colorectal, neuroendocrine, breast, and lung cancer, as well as uveal melanoma, cholangiocarcinoma, and sarcoma. Therapies discussed include bland transarterial embolization, chemoembolization, radioembolization, and ablative therapies, with a focus on current treatment approaches, outcomes of locoregional therapy, and future directions in each type of metastatic disease.

Microwave ablation combined with hepatectomy for treatment of neuroendocrine tumor liver metastases

BACKGROUND

Hepatectomy is the first choice for treating neuroendocrine tumor liver metastases. However, most patients with neuroendocrine tumor liver metastases are not suitable for hepatectomy. Ablation combined with hepatectomy can be an alternative to liver resection.

AIM

To explore the clinical effect of microwave ablation combined with hepatectomy for the treatment of neuroendocrine tumor liver metastases.

METHODS

In this study, the data of patients who underwent microwave ablation combined with hepatectomy for the treatment of neuroendocrine tumor liver metastases from June 2015 to January 2018 were reviewed. Before the operation, the patients did not receive any treatment for liver neuroendocrine tumors. After a multidisciplinary expert group discussion, all patients were deemed unsuitable for liver resection. All patients were diagnosed with neuroendocrine tumors by pathology. The overall survival time and progression-free survival time were followed by telephone calls and outpatient visits after surgery.

RESULTS

Eleven patients with neuroendocrine tumor liver metastases were treated by microwave ablation combined with hepatectomy between June 2015 and January 2018. The median number of liver metastatic nodules was 4 (range, 2 to 43). The median number of lesions resected was 1 (range, 1 to 18), and the median number of lesions ablated was 3 (range, 1 to 38). The mean operation time was 405.6 (± 39.4) min. The median intraoperative blood loss was 600 mL (range, 50 to 3000). Ten patients had a fever after surgery. The median duration of fever was 3 d (range, 0 to 21). Elevated bilirubin levels occurred in all patients after surgery. The median bilirubin on the first day after surgery was 28.5 (range, 10.7 to 98.9) µmol/L. One patient developed respiratory failure, renal insufficiency, and pneumonia after the operation. No patient died postoperatively during hospitalization. The mean overall survival time after surgery was 34.1 (± 3.7) mo, and the median progression-free survival time was 8 (range, 2 to 51) mo. One year after surgery, ten patients survived and five patients survived without progression. Three year after surgery, eight patients survived and two patients survived without progression.

CONCLUSION

Microwave ablation combined with hepatectomy not only makes the patients obtain a survival rate similar to that of patients undergoing hepatectomy, but also has a low incidence of postoperative complications.

Younger Age Is Associated with Improved Survival in Patients Undergoing Liver Transplantation Alone for Metastatic Neuroendocrine Tumors

BACKGROUND

Neuroendocrine tumor (NET) metastases are a major cause of morbidity and mortality. The role of liver transplantation to treat unresectable metastases from NET is controversial.

METHODS

We evaluated outcomes of all patients undergoing "isolated" liver transplantation (LT) for metastatic NETs in the USA, from October 1988 through June 2018 using the UNOS dataset.

RESULTS

During the study period, 160,360 LTs were performed. Two hundred six adult patients underwent "isolated" LT for metastatic NETs. The mean (SD) age was 48.2 (11.7) years, ranging from 19 to 75 years; 117 (56.8%) patients were male. Overall 1-, 3-, 5-, and 10-year patient survival rates were 89.1%, 75.3%, 64.9%, and 46.1%, respectively. Tumor recurrence was seen in 70 of 206 patients who underwent LT (34%). The median time to recurrence was 28 months (range, 1 to 192 months) and median wait time for LT was 112 days. Tumor recurrence was significantly higher in transplanted patients waiting less than 6 months compared with those waiting more than 6 months (74.3% vs. 25.7%). Patients' age ≤ 45 years had significantly better survival compared with those > 45 years (p = 0.03). Younger patients with carcinoid tumors had better survival but this trend was not observed in the non-carcinoid group. On multivariable analysis, recipient age, donor age, cold ischemic time MELD score, and tumor recurrence were significant predictors of poor patient survival.

CONCLUSIONS

Waiting time longer than 6 months is associated to lower rates of tumor recurrence. Younger patients ≤ 45 years had significantly improved survival after LT for NET metastases.

Treating Porcine Abscesses with Histotripsy: A Pilot Study

Infected abscesses are walled-off collections of pus and bacteria. They are a common sequela of complications in the setting of surgery, trauma, systemic infections and other disease states. Current treatment is typically limited to antibiotics with long-term catheter drainage, or surgical washout when inaccessible to percutaneous drainage or unresponsive to initial care efforts. Antibiotic resistance is also a growing concern. Although bacteria can develop drug resistance, they remain susceptible to thermal and mechanical damage. In particular, short pulses of focused ultrasound (i.e., histotripsy) generate mechanical damage through localized cavitation, representing a potential new paradigm for treating abscesses non-invasively, without the need for long-term catheterization and antibiotics. In this pilot study, boiling and cavitation histotripsy treatments were applied to subcutaneous and intramuscular abscesses developed in a novel porcine model. Ultrasound imaging was used to evaluate abscess maturity for treatment monitoring and assessment of post-treatment outcomes. Disinfection was quantified by counting bacteria colonies from samples aspirated before and after treatment. Histopathological evaluation of the abscesses was performed to identify changes resulting from histotripsy treatment and potential collateral damage. Cavitation histotripsy was more successful in reducing the bacterial load while having a smaller treatment volume compared with boiling histotripsy. The results of this pilot study suggest focused ultrasound may lead to a technology for in situ treatment of acoustically accessible abscesses.

A literature-based treatment algorithm for low-grade neuroendocrine liver metastases

BACKGROUND

The optimal timing of treatment of liver metastases from low-grade neuroendocrine tumors (LG-NELM) varies significantly due to numerous treatment modalities and the literature supporting various treatment(s). This study sought to create and validate a literature-based treatment algorithm for LG-NELM.

METHODS

A treatment algorithm to maximize overall survival (OS) was designed using peer-reviewed articles evaluating treatment of LG-NELM. This algorithm was retrospectively applied to patients treated for LG-NELM at our institution. Deviation was determined based on whether or not a patient received treatment consistent with that recommended by the algorithm. Patients who did and did not deviate from the algorithm were compared with respect to OS and number of treatments.

RESULTS

Applying our algorithm to a 149-patient cohort, 57 (38%) deviated from recommended treatment. Deviation occurred in the form of alternative (28, 49%) versus additional procedures (29, 51%). Algorithm deviators underwent significantly more procedures than non-deviators (median 1 vs. 2, p < 0.001). Cox model indicated no difference in OS associated with algorithm deviation (HR 1.19, p = 0.58) when controlling for age and tumor characteristics.

CONCLUSION

This literature-based algorithm helps standardize treatment protocols in patients with LG-NELM and can reduce cost and risk by minimizing unnecessary procedures. Prospective implementation and validation is required.

Frequency and risk factors for major complications after stereotactic radiofrequency ablation of liver tumors in 1235 ablation sessions: a 15-year experience

Objectives

To assess the frequency of major complications after multi-probe stereotactic radiofrequency ablation (SRFA) in a large cohort of patients over 15 years and to elucidate risk factors for adverse events.

Materials and methods

A retrospective study was carried out between July 2003 and December 2018. Seven hundred ninety-three consecutive patients (median 65.0 years (0.3–88), 241 women and 552 men, were treated in 1235 SRFA sessions for 2475 primary and metastatic liver tumors with a median tumor size of 3.0 cm (0.5–18 cm). The frequency of major complications was evaluated according to SIR guidelines and putative predictors of adverse events analyzed using simple and multivariable logistic regression.

Results

Thirty-day mortality after SRFA was 0.5% (6/1235) with an overall major complication rate of 7.4% (91/1235). The major complication rate decreased from 11.5% (36/314) (before January 2011) to 6.0% (55/921) (p = 0.001). 50.5% (46/91) of major complications were successfully treated in the same anesthetic session by angiographic coiling for hemorrhage and chest tube insertion for pneumothorax. History of bile duct surgery/intervention, number of coaxial needles, and location of tumors in segment IVa or VIII were independent prognostic factors for major complications following multivariable logistic regression analysis. Simple logistic regression revealed the number of tumors, tumor size, location close to the diaphragm, tumor conglomerate, and segment VII as other significant predictors.

Conclusion

SRFA of liver tumors is safe and can extend the treatment spectrum of conventional RFA. Adaptations over time combined with increasing experience resulted in a significant decrease in complications.

Key Points

• In 1235 ablation sessions in 793 patients over 15 years, we found a mortality rate of 0.5% (6/1235) and an overall major complication rate of 7.4%, which fell from 11.5 (36/314) to 6.0% (55/921, p = 0.001) after January 2011, likely due to procedural adaptations.

• History of bile duct surgery/intervention (p = 0.013, OR = 3.290), number of coaxial needles (p = 0.026, OR = 1.052), and location of tumors in segment IVa (p = 0.016, OR = 1.989) or VIII (p = 0.038, OR = 1.635) were found to be independent prognostic factors.

• Simple logistic regression revealed that number of tumors, tumor size, location close to the diaphragm, tumor conglomerates, and segment VII were other significant predictors of major complications.

Neuroendocrine liver metastases: a contemporary review of treatment strategies

Well-differentiated neuroendocrine tumors (NETs) are globally increasing in prevalence and the liver is the most common site of metastasis. Neuroendocrine liver metastases (NELM) are heterogeneous in clinical presentation and prognosis. Fortunately, recent advances in diagnostic techniques and therapeutic strategies have improved the multidisciplinary management of this challenging condition. When feasible, surgical resection of NELM offers the best long-term outcomes. General indications for hepatic resection include performance status acceptable for major liver surgery, grade 1 or 2 tumors, absence of extrahepatic disease, adequate size and function of future liver remnant, and feasibility of resecting >90% of metastases. Adjunct therapies including concomitant liver ablation are generally safe when used appropriately and may expand the number of patients eligible for surgery. Among patients with synchronous resectable NELM, resection of the primary either in a staged or combined fashion is recommended. For patients who are not surgical candidates, liver-directed therapies such as transarterial embolization, chemoembolization, and radioembolization can provide locoregional control and improve symptoms of carcinoid syndrome. Multiple systemic therapy options also exist for patients with advanced or progressive disease. Ongoing research efforts are needed to identify novel biomarkers that will define the optimal indications for and sequencing of treatments to be delivered in a personalized fashion.

Liver-directed therapies for liver metastases from neuroendocrine neoplasms: Can laser ablation play any role?

Aggressive cytoreduction can prolong survival in patients with unresectable liver metastases (LM) from neuroendocrine neoplasms (NEN), and minimally invasive, liver-directed therapies are gaining increasing interest. Catheter-based treatments are used in disseminated disease, whereas ablation techniques are usually indicated when the number of LM is limited. Although radiofrequency ablation (RFA) is by far the most used ablative technique, the goal of this opinion review is to explore the potential role of laser ablation (LA) in the treatment of LM from NEN. LA uses thinner needles than RFA, and this is an advantage when the tumors are in at-risk locations. Moreover, the multi-fiber technique enables the use of one to four laser fibers at once, and each fiber provides an almost spherical thermal lesion of 12-15 mm in diameter. Such a characteristic enables to tailor the size of each thermal lesion to the size of each tumor, sparing the liver parenchyma more than any other liver-directed therapy, and allowing for repeated treatments with low risk of liver failure. A recent retrospective study reporting the largest series of LM treated with LA documents both safety and effectiveness of LA, that can play a useful role in the multimodality approach to LM from NEN.

Surgical management of pancreatic neuroendocrine liver metastases

Pancreatic neuroendocrine tumors (PNET) are a heterogeneous group of neoplasms that vary in their clinical presentation, behavior and prognosis. The most common site of metastasis is the liver. Surgical resection of neuroendocrine liver metastases (NELM) is thought to afford the best long-term outcomes when feasible. Initial preoperative workup should include surveillance for carcinoid syndrome, screening for evidence of liver insufficiency, and performance of imaging specific to neuroendocrine tumors such as a somatostatin receptor positron emission tomography scan. Standard surgical principles apply to hepatic surgery for NELM, namely prioritizing low central venous pressure anesthesia, minimizing blood loss, knowledge of liver anatomy, generous use of intraoperative ultrasound, as well as safe parenchymal transection techniques and practices to avoid bile leakage. Knowledge of established prognostic factors may assist with patient selection, which is important for optimizing short- and long-term outcomes of hepatic resection. Adjunct therapies such as concomitant liver ablation are used frequently and are generally safe when used appropriately. For patients with synchronous resectable NELM, resection of the primary either in a staged or combined fashion is recommended. Primary tumor resection in the setting of unresectable metastatic disease is more controversial, however generally recommended if morbidity is acceptable. For patients who are not surgical candidates, due to either patient performance status or burden of liver disease, several liver-directed therapies such as transarterial embolization, chemoembolization, and radioembolization are available to assist with locoregional control, extend progression-free survival (PFS), and improve symptoms of carcinoid syndrome. Multiple systemic therapy options exist for patients with metastatic PNET which are often prioritized for those patients with advanced or progressive disease. A systematic approach in a multi-disciplinary setting is likely to result in the best long-term outcomes for patients with pancreatic NELM. Ongoing research is needed to determine the optimal patient selection for hepatic surgery as well as the ideal treatment sequencing for those patients with NELM.

Midgut Neuroendocrine Tumors with Liver-only Metastases: Benefit of Primary Tumor Resection

BACKGROUND

Management of metastatic midgut neuroendocrine tumors (MNET) remains controversial. The benefits of resecting the primary tumor are not clear and advocated only for select patients. This study aimed to determine whether resection of the primary MNET in patients with untreated liver-only metastases has an impact on survival.

METHODS

This retrospective study reviewed data of the National Cancer Database from 2004 to 2015 for patients with liver-only metastatic MNETs and compared those who received resection of their primary MNET with those who did not. Patient demographics, tumor characteristics, and clinical outcomes were compared between the groups. The primary outcome was overall survival (OS) after adjustment for patient, demographic, and tumor-related factors.

RESULTS

The study identified 1952 patients with a median age of 63 years (range, 18-90 years). The median primary tumor size was 2.4 cm (range, 0.1-20 cm). Of these patients, 1295 (66%) underwent resection of the primary tumor and 667 (34%) did not. The patients who underwent resection were younger (median age, 63 vs 65 years; p < 0.001) and had smaller primary tumors (median, 2.3 vs 3.0 cm; p < 0.001). The patients with clinical T1 or T2 tumors were significantly less likely to undergo resection than those with stage T3 or T4 tumors (58.5% vs 89.7%; p < 0.001). The median follow-up period was 43 months (range, 1-83 months). In the entire cohort, 483 deaths occurred, with a 5-year OS of 61%. The 5-year OS rate was 49% for the patients who underwent resection and 66% for those who did not (p < 0.001). When the patients were grouped according to T stage, no OS difference between resection and no resection for stages T1 (p = 0.07) and T2 (p = 0.40) was identified. However, the 5-year OS rate was significantly better for the resected patient cohort with T3 (67.5% vs 37.2%; p < 0.001) or T4 (59.8% vs 21.5%; p < 0.001) tumors.

CONCLUSIONS

The patients with treatment-naïve liver-only metastatic MNET had improved OS when the primary tumor was resected, particularly those with clinical stage T3 or T4 tumors. These patients may benefit from surgical resection of their primary tumor.

Resection of the Primary Gastrointestinal Neuroendocrine Tumor Improves Survival With or Without Liver Treatment

OBJECTIVE

The aim of this study was to determine outcomes of primary tumor resection in metastatic neuroendocrine tumors across all primary tumor sites.

BACKGROUND

Primary tumor resection (PTR) may offer a survival benefit in metastatic gastrointestinal neuroendocrine tumors (GI-NETs); however, few studies have examined the effect of primary site and grade on resection and survival.

METHODS

This is a retrospective study of patients with metastatic GI-NETs at presentation between 2005 and 2011 using the California Cancer Registry (CCR) dataset merged with California Office of Statewide Health Planning and Development (OSHPD) inpatient longitudinal database. Primary outcome was overall survival (OS). Univariate and multivariate (MV) analyses were performed using the Pearson Chi-squared tests and Cox proportional hazard, respectively. OS was estimated using the Kaplan-Meier method and log-rank test.

RESULTS

A total of 854 patients with GI-NET metastases on presentation underwent 392 PTRs. Liver metastases occurred in 430 patients; 240 received liver treatment(s). PTR improved OS in patients with untreated metastases (median survival 10 vs 38 months, P < 0.001). On MV analysis adjusted for demographics, tumor stage, grade, chemotherapy use, Charlson comorbidity index, primary tumor location, or treatment of liver metastases, PTR with/without liver treatment improved OS in comparison to no treatment [hazard ratio (HR) 0.50, P < 0.001 and 0.39, P < 0.001, respectively]. PTR offered a survival benefit across all grades (low-grade, HR 0.38, P = 0.002 and high-grade, HR 0.62, P = 0.025) CONCLUSION:: PTR in GI-NET is associated with a better survival, with or without liver treatment, irrespective of grade. This study supports the resection of the primary tumor in patients with metastatic GI-NETs, independent of liver treatment.

Percutaneous Laser Ablation of Liver Metastases from Neuroendocrine Neoplasm. A Retrospective Study for Safety and Effectiveness

PURPOSE

To retrospectively assess safety and efficacy of laser ablation (LA) of multiple liver metastases (LM) from neuroendocrine neoplasms (NEN).

METHODS

Twenty-one patients with NEN and at least 3 LM ≤ 4 cm in diameter underwent ultrasonography-guided LA. Up to seven LM were ablated in a single session; if the number of LM exceeded seven, the remaining LM were ablated in further LA sessions with a time interval of 3-4 weeks. LA was performed according to the multifiber technique. The patients underwent contrast-enhanced CT 1 month after LA, and were subsequently monitored every 3 months for the first 2 years and then every 6 months.

RESULTS

In total, 189 LM were treated in 21 patients (mean 9 ± 8.2, median 6) in 41 LA sessions (range 1-5). The diameter of LM ranged from 5 to 35 mm (median 19 mm, mean 17.9 ± 6.4 mm). One grade 4 complication occurred (0.53%): a bowel perforation managed by surgery. Technical efficacy was 100%, primary efficacy rate 94.7%, and secondary efficacy rate 100%. Complete relief of hormone-related symptoms was obtained in all the 13 symptomatic patients. Median follow-up was 39 months (range 12-99). 1-, 2-, 3-, and 5-year survival rates were 95%, 86%, 66%, and 40%, respectively. Overall survival resulted higher for patients with Ki-67 expression ≤ 7% than for those with Ki-67 > 7% (p = 0.0347).

CONCLUSIONS

LA is a promising and safe technique to treat LM from NEN. A longer follow-up should provide definitive information on the long-term efficacy of this liver-directed therapy.

LEVEL OF EVIDENCE

Retrospective study, local non-random sample, level 3.

Prediction of Local Tumor Progression after Radiofrequency Ablation (RFA) of Hepatocellular Carcinoma by Assessment of Ablative Margin Using Pre-RFA MRI and Post-RFA CT Registration

Objective

To evaluate the clinical impact of using registration software for ablative margin assessment on pre-radiofrequency ablation (RFA) magnetic resonance imaging (MRI) and post-RFA computed tomography (CT) compared with the conventional side-by-side MR-CT visual comparison.

Materials and Methods

In this Institutional Review Board-approved prospective study, 68 patients with 88 hepatocellulcar carcinomas (HCCs) who had undergone pre-RFA MRI were enrolled. Informed consent was obtained from all patients. Pre-RFA MRI and post-RFA CT images were analyzed to evaluate the presence of a sufficient safety margin (≥ 3 mm) in two separate sessions using either side-by-side visual comparison or non-rigid registration software. Patients with an insufficient ablative margin on either one or both methods underwent additional treatment depending on the technical feasibility and patient's condition. Then, ablative margins were re-assessed using both methods. Local tumor progression (LTP) rates were compared between the sufficient and insufficient margin groups in each method.

Results

The two methods showed 14.8% (13/88) discordance in estimating sufficient ablative margins. On registration software-assisted inspection, patients with insufficient ablative margins showed a significantly higher 5-year LTP rate than those with sufficient ablative margins (66.7% vs. 27.0%, p = 0.004). However, classification by visual inspection alone did not reveal a significant difference in 5-year LTP between the two groups (28.6% vs. 30.5%, p = 0.79).

Conclusion

Registration software provided better ablative margin assessment than did visual inspection in patients with HCCs who had undergone pre-RFA MRI and post-RFA CT for prediction of LTP after RFA and may provide more precise risk stratification of those who are treated with RFA.

Surgical management of neuroendocrine tumor-associated liver metastases: a review

Liver metastasis is common among patients who suffer from neuroendocrine tumors (NETs). Radical surgery is the standard treatment whenever possible but there is still controversies concerning the treatment strategies such as resection of the primary, role of debulking surgery, liver transplantation (LT) and neoadjuvant or adjuvant therapies. This article aims to review the current evidence available, together with some latest updates, focusing on the surgical management.

Complications of liver resection in geriatric patients

Introduction and aims. Liver resection is the treatment of choice for many primary and secondary liver diseases. Most studies in the elderly have reported resection of primary and secondary liver tumors, especially hepatocellular carcinoma and colorectal metastatic cancer. However, over the last two decades, hepatectomy has become safe and is now performed in the older population, implying a paradigm shift in the approach to these patients.

MATERIAL AND METHODS

We retrospectively evaluated the risk factors for postoperative complications in patients over 65 years of age in comparison with those under 65 years of age after liver resection (n = 360). The set comprised 127 patients older than 65 years (35%) and 233 patients younger than 65 years (65%).

RESULTS

In patients younger than 65 years, there was a significantly higher incidence of benign liver tumors (P = 0.0073); in those older than 65 years, there was a significantly higher incidence of metastasis of colorectal carcinoma to the liver (0.0058). In patients older than 65 years, there were significantly more postoperative cardiovascular complications (P = 0.0028). Applying multivariate analysis, we did not identify any independent risk factors for postoperative complications. The 12-month survival was not significantly different (younger versus older patients), and the 5-year survival was significantly worse in older patients (P = 0.0454).

CONCLUSION

In the case of liver resection, age should not be a contraindication. An individualized approach to the patient and multidisciplinary postoperative care are the important issues.

Surgical management for non-functional pancreatic neuroendocrine neoplasms with synchronous liver metastasis: A consensus from the Chinese Study Group for Neuroendocrine Tumors (CSNET)

Pancreatic neuroendocrine neoplasms (p-NENs) are slowly growing tumors with frequent liver metastasis. There is a variety of approaches to treat non-functional p-NENs with synchronous liver metastasis (LM) which complicates the determination of optimal treatment. Based on updated literature review, we discussed the treatment strategy determinants for p-NEN with LM. According to the resectability of primary tumor, the WHO 2010 grade classification and the radiological type of liver metastasis, the CSNET group reached agreements on a number of issues, including the following. Prior to treatment, biopsy is required to confirm pathology. Liver biopsy is important for more accurate grading of tumor and percutaneous core needle biopsy is more available than EUS-FNA. In patients with unresectable primary, surgical resection for liver-metastatic lesions should be avoided. Curative surgery is recommended for G1/G2 p-NET with type I LM and R1 resection also seems to improve overall survival rate. Cytoreductive surgery is recommended for G1/G2 p-NET with type II LM in select patients, and should meet stated requirements. Surgical resection for G1/G2 p-NET with type III LM and p-NEC with LM should be avoided, and insufficient evidence exists to guide the surgical treatment of G3 p-NET with LM. Liver transplantation may be an option in highly select patients. In addition, the optimal time for surgical approach is still required for more evidence.

Hepatic Tumor Ablation

Tumor ablation is a safe and effective treatment available in the multidisciplinary care of the surgical oncology patient. The role of ablation is well established in the treatment of hepatocellular carcinoma and is becoming more accepted in the treatment of various malignancies metastatic to the liver, in particular colorectal cancer. Understanding the underlying technology, achieving appropriate applicator placement, using maximum energy delivery to create margins, and performing necessary adjunctive maneuvers are all required for successful tumor ablation.

Liver-directed surgery of neuroendocrine metastases: What is the optimal strategy?

INTRODUCTION

Neuroendocrine tumors (NETs) frequently metastasize to the liver. Operative debulking offers symptomatic relief and improved survival; however, the frequent presence of multifocal, bilobar disease and high recurrence rates introduces doubt regarding their optimal management. Parenchyma-sparing debulking (PSD) procedures (ablation, enucleation, wedge resections) may offer similar survival improvements as resection while minimizing morbidity and preserving functional liver tissue.

METHODS

Clinicopathologic variables from 228 patients with small bowel or pancreatic NETs managed operatively at one institution were collected. Liver-directed surgery was carried out when substantial debulking was deemed feasible. Survival was assessed by use of the Kaplan-Meier method.

RESULTS

A total of 108 patients with pancreatic NET or small bowel NET underwent liver-directed surgery with primarily PSD procedures. Nearly two-thirds of patients achieved 70% cytoreduction and 84% had concurrent resection of their primary. The median number of lesions treated was 6 (range, 1-36). There were no 30-day operative mortalities. The 30-day major complication rate was 13.0%. Patients who achieved 70% cytoreduction enjoyed improved progression free (median 3.2 years) and overall survival (median not reached).

CONCLUSION

PSD procedures are safe and can achieve significant cytoreduction, which is associated with improved survival. Lowering the debulking target threshold to 70% may benefit NET patients by increasing eligibility for cytoreduction.

Aggressive Locoregional Treatment Improves the Outcome of Liver Metastases from Grade 3 Gastroenteropancreatic Neuroendocrine Tumors

Grade 3 (G3) gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are rare, and there is no report specifically dealing with patients of liver metastases from G3 GEP NETs.From January 2004 to January 2014, 36 conservative patients with G3 GEP NET liver metastases were retrospectively identified from 3 hepatobiliary centers in China. The clinical features and treatment outcomes were analyzed.Aggressive locoregional treatments (LT, including cytoreductive surgery, radiofrequency ablation, and liver-directed intra-arterial intervention) and systemic therapy (ST) were introduced separately or combined, with 26 (72%) patients receiving resection of primary tumor and/or hepatic metastases, 12 patients receiving non-surgical locoregional interventions (NSLRIs), and 22 patients receiving certain kind of STs. Median overall survival (OS) was 20.0 months (95% confidence interval [CI]: 8.9-31.1 months) and survival rates were 62.6%, 30.1%, and 19.8%, at 1, 3, and 5 years, respectively. The median OS was 9.0 months (95%CI: 3.3-14.7 months) for patients receiving only STs (n = 6), 19 months (95%CI: 1.3-36.8 months) for patients receiving LT followed by STs (n = 16), and 101 months (95%CI: 0.0-210.2 months) for patients receiving only LT (n = 12). Moreover, compared with those receiving only ST or best supportive care, patients given certain types of LTs had higher rates of symptom alleviation (3/8 versus 20/23). On univariate analysis, positive prognostic factors of survival were pancreatic primary tumor (P = 0.013), normal total bilirubin level (P = 0.035), receiving surgery (P = 0.034), receiving NSLRI (P = 0.014), and sum of diameters of remnant tumor < 5 cm (P = 0.008). On multivariate analyses, pancreatic primary tumor (P = 0.015), normal total bilirubin level (P = 0.002), and sum of diameters of remnant tumor < 5 cm (P = 0.001) remained to be independent prognostic factors.For patients with G3 GEP NET liver metastases, aggressive LTs may improve clinical outcomes. Larger studies with prospective design are warranted to consolidate these results, and to discover the most appropriate seletion criteria for patients to undergo different kinds of aggressive LTs and to find the most effective combinations, with or without ST.

Long-Term Survival with Long-Acting Somatostatin Analogues Plus Aggressive Cytoreductive Surgery in Patients with Metastatic Neuroendocrine Carcinoma

BACKGROUND

Long-acting somatostatin analogues (S-LAR) improve recurrence-free survival in patients with metastatic neuroendocrine tumor (NET) from gastrointestinal (GI) primary, but their impact on overall survival when combined with aggressive cytoreductive surgery is unclear.

STUDY DESIGN

We reviewed our institutional cancer database to identify patients who underwent cytoreductive surgery for metastatic NET from GI primary between December 1997 and June 2013. Additionally, a cohort selected from 3,384 metastatic neuroendocrine cases in the SEER-Medicare database (January 2003 to December 2009) was used to verify and expand on our results.

RESULTS

Most of the 49 patients from our institution had primary lesions in the small intestine (22 of 49 [44.9%]) or pancreas (14 of 49 [28.6%]); 37 patients (75.5%) had metastatic disease at initial diagnosis. These patients underwent 1 (32 of 49 [65.3%]), 2 (11 of 49 [22.4%]), or at least 3 (6 of 49 [12.3%]) surgical procedures; 33 patients (67.3%) underwent resection plus ablation, 19 (38.7%) underwent major hepatectomy, and 34 (69.4%) received S-LAR (29.4% administered preoperatively). Median follow-up was 112 months. Rates of 1-, 5-, 10-, and 15-year disease-specific survival (DSS) were 94%, 78%, 64%, and 31%, respectively, in the 34 patients undergoing aggressive cytoreductive surgery plus S-LAR. Of the SEER-Medicare population, 1,741 patients met inclusion criteria. The DSS for the 104 patients treated with combination therapy was 68.3% at 5 years and 60.6% at 10 years, as compared with 54.7% and 51.8%, respectively, for the 202 patients receiving surgery alone, and 50.0% and 36.0%, respectively, for the 342 patients receiving S-LAR alone (p < 0.0001). The group receiving neither treatment (n = 1,093) had 5-year and 10-year DSS of 34.3% and 26.3%, respectively.

CONCLUSIONS

Long-acting somatostatin analogues combined with aggressive cytoreductive surgery improves the long-term survival of select patients with metastatic NET from GI primary.

Radiofrequency ablation for neuroendocrine liver metastases: a systematic review

To determine the efficacy of radiofrequency (RF) ablation in neuroendocrine tumor (NET) liver metastases. A systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eight studies were included (N = 301). Twenty-six percent of RF ablation procedures were percutaneous (n = 156), with the remainder conducted at surgery. Forty-eight percent of patients had a concomitant liver resection. Fifty-four percent of patients presented with symptoms, with 92% reporting symptom improvement following RF ablation (alone or in combination with surgery). The median duration of symptom improvement was 14-27 months. However, recurrence was common (63%-87%). RF ablation can provide symptomatic relief in NET liver metastases alone or in combination with surgery.

Liver metastases of small intestine neuroendocrine tumors: Ki-67 heterogeneity and World Health Organization grade discordance with primary tumors

OBJECTIVES

We examined Ki-67 heterogeneity within single and between synchronous liver metastases of small intestine neuroendocrine tumors.

METHODS

There were 27 patients (10 men and 17 women) with two or more liver metastases. The Ki-67 index was used to classify the tumors into World Health Organization grade 1, 2, or 3. The association between Ki-67 heterogeneity and tumor size of liver metastases was analyzed. Correlation of tumor grade with patient survival was also evaluated.

RESULTS

Primary tumors from 20 patients were graded, including 17 grade 1 and three grade 2. A total of 188 liver metastases were resected, including 122 (65%) grade 1, 47 (25%) grade 2, and 19 (10%) grade 3. The highest tumor grade was grade 1 in 10 (37%), grade 2 in nine (33%), and grade 3 in eight (30%) patients. Patients with one or more grade 3 liver lesions had a shorter progression-free survival compared with those with grade 1/2 tumors (P < .001). A positive association was found between tumor size and Ki-67 index (P = .04), as well as between tumor size and intratumoral Ki-67 heterogeneity (P < .001).

CONCLUSIONS

Intratumoral and intertumoral Ki-67 heterogeneity is common and positively correlated with tumor size. The presence of one or more grade 3 liver lesions predicts a worse prognosis.

Curative versus palliative surgical resection of liver metastases in patients with neuroendocrine tumors: a meta-analysis of observational studies

BACKGROUND

The role of surgical therapy in patients with liver metastases from neuroendocrine tumors (NETs) is unclear. In this study, the results obtained with curative or palliative resection, by reviewing recent literature and performing a meta-analysis, were examined.

MATERIALS AND METHODS

A systematic review and meta-analysis of observational studies published between January 1990 and October 2013 were performed. Studies that evaluated the different survival between patients treated by curative or palliative surgical resection of hepatic metastases from NETs were considered. The collected studies were evaluated for heterogeneity, publication bias, and quality. To calculate the pooled hazard ratio (HR) estimate and the 95% confidence interval (95% CI), a fixed-effects model was applied.

RESULTS

After the literature search, 2,546 studies were found and, among 38 potentially eligible studies, 3 were considered. We did not find a significant longer survival in patients treated with curative surgical resection of hepatic metastases when compared to palliative hepatic resection HR 0.40 (95% CI: 0.14-1.11). In one study, palliative resection of hepatic metastases significantly increased survival when compared to embolization.

CONCLUSIONS

Curative and also palliative surgery of NETs liver metastases may improve survival outcome. However, further randomized clinical trials are needed to elucidate this argument.

Update on pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (pNETs) are relatively rare tumors comprising 1-2% of all pancreas neoplasms. In the last 10 years our understanding of this disease has increased dramatically allowing for advancements in the treatment of pNETs. Surgical excision remains the primary therapy for localized tumors and only potential for cure. New surgical techniques using laparoscopic approaches to complex pancreatic resections are a major advancement in surgical therapy and increasingly possible. With early detection being less common, most patients present with metastatic disease. Management of these patients requires multidisciplinary care combining the best of surgery, chemotherapy and other targeted therapies. In addition to surgical advances, recently, there have been significant advances in systemic therapy and targeted molecular therapy.

Ablative technologies for hepatocellular, cholangiocarcinoma, and metastatic colorectal cancer of the liver

A wide array of ablation technologies, in addition to the progressive sophistication of imaging technologies and percutaneous, laparoscopic, and open surgical techniques, have allowed us to expand treatment options for patients with liver tumors. In this article, technical considerations of chemical and thermal ablations and their application in hepatic oncology are reviewed.

Role of surgery and transplantation in the treatment of hepatic metastases from neuroendocrine tumor

Neuroendocrine tumors (NET) are a heterogeneous group of cancers, with indolent behavior. The most common primary origin is the gastro-intestinal tract but can also appear in the lungs, kidneys, adrenals, ovaries and other organs. In general, NET is usually discovered in the metastatic phase (40%-80%). The liver is the most common organ involved when metastases occur (40%-93%), followed by bone (12%-20%) and lung (8%-10%).A number of different therapeutic options are available for the treatment of hepatic metastases including surgical resection, transplantation, ablation, trans-arterial chemoembolization, chemotherapy and somatostatin analogues. Recently, molecular targeted therapies have been used, usually in combination with other treatment options, to improve outcomes in patients with metastases. This article emphasizes on the role of surgery in the treatment of liver metastases from NET.

Gene expression accurately distinguishes liver metastases of small bowel and pancreas neuroendocrine tumors

Small bowel (SBNETs) and pancreatic neuroendocrine tumors (PNETs) often present with liver metastases. Although liver biopsy establishes a neuroendocrine diagnosis, the primary tumor site is frequently unknown without exploratory surgery. Gene expression differences in metastases may distinguish primary SBNETs and PNETs. This study sought to determine expression differences of four genes in neuroendocrine metastases and to create a gene expression algorithm to distinguish the primary site. Nodal and liver metastases from SBNETs and PNETs (n = 136) were collected at surgery under an Institutional Review Board-approved protocol. Quantitative PCR measured expression of bombesin-like receptor-3, opioid receptor kappa-1, oxytocin receptor, and secretin receptor in metastases. Logistic regression models defined an algorithm predicting the primary tumor site. Models were developed on a training set of 21 nodal metastases and performance was validated on an independent set of nodal and liver metastases. Expression of all four genes was significantly different in SBNET compared to PNET metastases. The optimal model employed expression of bombesin-like receptor-3 and opioid receptor kappa-1. When these genes did not amplify, the algorithm used oxytocin receptor and secretin receptor expression, which allowed classification of all 136 metastases with 94.1 % accuracy. In the independent liver metastasis validation set, 52/56 (92.9 %) were correctly classified. Positive predictive values were 92.5 % for SBNETs and 93.8 % for PNETs. This validated algorithm accurately distinguishes SBNET and PNET metastases based on their expression of four genes. High accuracy in liver metastases demonstrates applicability to the clinical setting. Studies assessing this algorithm's utility in prospective clinical decision-making are warranted.

Pancreastatin predicts survival in neuroendocrine tumors

BACKGROUND

Serum neurokinin A, chromogranin A, serotonin, and pancreastatin reflect tumor burden in neuroendocrine tumors. We sought to determine whether their levels correlate with survival in surgically managed small bowel (SBNETs) and pancreatic neuroendocrine tumors (PNETs).

METHODS

Clinical data were collected with Institutional Review Board approval for patients undergoing surgery at one center. Progression-free (PFS) and overall (OS) survival were from the time of surgery. Event times were estimated by the Kaplan-Meier method. Preoperative and postoperative laboratory values were tested for correlation with outcomes. A multivariate Cox model adjusted for confounders.

RESULTS

Included were 98 SBNETs and 78 PNETs. Median follow-up was 3.8 years; 62 % had metastatic disease. SBNETs had lower median PFS than PNETs (2.0 vs. 5.6 years; p < 0.01). Median OS was 10.5 years for PNETs and was not reached for SBNETs. Preoperative neurokinin A did not correlate with PFS or OS. Preoperative serotonin correlated with PFS but not OS. Higher levels of preoperative chromogranin A and pancreastatin showed significant correlation with worse PFS and OS (p < 0.05). After multivariate adjustment for confounders, preoperative and postoperative pancreastatin remained independently predictive of worse PFS and OS (p < 0.05). Whether pancreastatin normalized postoperatively further discriminated outcomes. Median PFS was 1.7 years in patients with elevated preoperative pancreastatin versus 6.5 years in patients with normal levels (p < 0.001).

CONCLUSIONS

Higher pancreastatin levels are significantly associated with worse PFS and OS in SBNETs and PNETs. This effect is independent of age, primary tumor site, and presence of nodal or metastatic disease. Pancreastatin provides valuable prognostic information and identifies surgical patients at high risk of recurrence who could benefit most from novel therapies.