Clinically Significant Differences in Ki-67 Proliferation Index Between Primary and Metastases in Resected Pancreatic Neuroendocrine Tumors

High rate of Ki-67 increase in entero-pancreatic NET relapses after surgery with curative intent

Neuroendocrine neoplasms (NENs) present with advanced disease at diagnosis in up to 28% of cases, precluding the possibility of curative-intent surgery. Histopathological heterogeneity of this disease can be observed inter-individually as well as intra-individually during disease course. The present study aimed to assess the frequency of Ki-67 change after radical surgery, in a series of patients with radically resected entero-pancreatic neuroendocrine tumors (EP-NETs). We present the analysis of a multicenter, retrospective, series of EP-NETs G1-G2 recurring after radical resection and with histological re-evaluation at disease recurrence (DR). The primary endpoint was the description of Ki-67 change at DR compared to time of surgery. The secondary endpoint was assessment of recurrence-free survival (RFS) rates. In total, 47 patients had a second histological evaluation and could be included in the present study. Median Ki-67 at surgery was 3% (range 1-15%) but, at DR, a significant increase in the value was observed (7%, range 1-30%; p < .01) and involved 66.0% of cases, with a corresponding increase in tumor grading in 34.0% (p = .05). Median RFS of the overall population was 40 months, and was worse when Ki-67 increased at DR vs. stable Ki-67 value (36 vs. 61 months, respectively; p = .02). In conclusion, in more than half of the cases with relapse after radical surgery, a higher proliferative index with a potentially more aggressive potential was observed. Therefore, histological reassessment should be considered on DR because tailored therapeutic strategies may be required for these patients.

A real-life treatment cohort of pancreatic neuroendocrine tumors: High-grade increase in metastases confers poor survival

BACKGROUND

Tumor grade determined by the Ki67 index is the best prognostic factor for pancreatic neuroendocrine tumors (PanNETs). However, we often observe that the grade of metastases differs from that of their primary tumors. This study aimed to investigate the frequency of grade changes between primary tumors and metastases, explore its association with clinical characteristics, and correlate the findings with the prognosis.

METHODS

Six hundred forty-eight patients with pancreatic neuroendocrine neoplasms treated at Fudan University Shanghai Cancer Center were screened for inclusion, and 103 patients with PanNETs who had paired primary tumors and metastases with an available Ki67 index were included. Re-evaluation of Ki67 was performed on 98 available samples from 69 patients.

RESULTS

Fifty cases (48.5%) had a Ki67 index variation, and 18 cases (17.5%) displayed a grade increase. Metachronous metastases showed significantly higher Ki67 index variation than synchronous metastases (P=0.028). Kaplan-Meier analyses showed that high-grade metastases compared to low-grade primary tumors were significantly associated with decreased progression-free survival (PFS, P=0.012) and overall survival (OS, P=0.027). Multivariable Cox regression analyses demonstrated that a low-grade increase to high-grade was an unfavorable and independent prognostic factor for PFS and OS (P=0.010, and P=0.041, respectively).

CONCLUSIONS

A high-grade increase in metastases was an unfavorable predictor of PanNETs, which emphasized the importance of accurate pathological grading and could provide a reference for clinical decision-making.

Pituitary metastases from neuroendocrine neoplasms: case report and narrative review

PURPOSE

Pituitary metastases (PM) are uncommon findings and are mainly derived from breast and lung cancers. No extensive review of PM from neuroendocrine neoplasms (NENs) is on record. Here we describe a clinical case of PM from pancreatic NEN and review the clinical features of PM from NENs reported in the literature.

METHODS

A case of PM from a pancreatic NEN followed at our institution is described. We also reviewed the 43 cases of PM from NENs reported in the literature.

RESULTS

A 59-year old female patient, previously submitted to duodeno-cephalo-pancreasectomy for a well-differentiated pancreatic NEN, with known hepatic metastases, underwent a ⁶⁸ Ga-DOTATOC PET/CT that revealed an uptake in the pituitary gland. A subsequent MRI displayed a pituitary lesion, with suprasellar extension. After a hormonal and genetic diagnostic workup that excluded the diagnosis of MEN 1, the worsening of headache and visual impairment and the growth of the lesion lead to its surgical removal. A pituitary localization of the pancreatic NEN was identified. Regarding the published cases of PM from NENs, the most common tumour type was small cell lung cancer (SCLC), accounting for nearly half of the cases, followed by bronchial and pancreatic well differentiated NENs. The most frequent symptom was a variable degree of visual impairment, while headache was reported in half of the cases. Partial or total anterior hypopituitarism was present in approximately three quarters of the cases, while diabetes insipidus was less common. The most frequent treatment for PM was surgical resection, followed by radiotherapy and chemotherapy. The clinical outcome was in line with previous reports of PM from solid tumours, with a median survival of 14 months. Surgery of PM was associated with prolonged survival.

CONCLUSIONS

PM from NENs have clinical features similar to metastases derived from other solid tumours, albeit the involvement of the anterior pituitary seems more frequent; a thorough pituitary hormonal evaluation is mandatory, after focused radiological studies, particularly if a surgical approach is considered. The optimal management of PM remains disputed and seems mainly driven by the aggressiveness of the primary tumour and the presence of symptoms. In well-differentiated NENs, particularly in the case of symptomatic PM, surgical removal may be a reasonable approach.

Increase of Ki-67 index and influence on mortality in patients with neuroendocrine neoplasms

An increase in the Ki-67 index in neuroendocrine neoplasms over time in relation to prognosis has scarcely been investigated. We aimed to assess whether the Ki-67 index changed over time and also whether a change influenced prognosis. Second, we investigated the difference in the Ki-67 index between primary tumour and metastases. From 1 January 1995 to 31 December 2019, 108 consecutive patients with gastroenteropancreatic tumours were included. Patients were followed with regard to an increase in the Ki-67 index and all-cause mortality. Ki-67 determination of the primary tumour at diagnosis and at the time of radiological progression, including developed metastases, was performed. A significant increase in the Ki-67 index was defined as a doubling of the value at disease progression compared to the value at diagnosis. In addition, in 14 patients, the Ki-67 index of the primary tumour and present metastases at the time of diagnosis was investigated. At diagnosis, there were no differences in the Ki-67 index between primary tumours and metastases (P = .41). Sixty-five patients had a doubling of the Ki-67 index. The median Ki-67 index at the time of progression 17% (1%-90%) vs 5% (1%-60%) at the time of diagnosis (P = .006). A doubling of the Ki-67 index was independently associated with all-cause mortality (hazard ratio = 2.7 [1.3-6.3], P = 0.02), after adjustment for relevant co-variables including the Ki-67 index at baseline. Doubling of the Ki-67 index at the time of disease progression was associated with a significantly higher risk of all-cause mortality. We recommend that a Ki-67 index is obtained whenever disease progression is recorded by demonstrated progression because it may have impact on the choice of treatment.

Survey of surgical resections for neuroendocrine liver metastases: A project study of the Japan Neuroendocrine Tumor Society (JNETS)

BACKGROUND/PURPOSE

Hepatic resection is considered the treatment of choice for neuroendocrine liver metastases (NELM). However, the safety and efficacy of resection have not been fully evaluated using a large cohort. The aim of the present study was to collect real-world data regarding hepatic resections for NELM.

METHODS

A retrospective, multicenter survey was conducted. The background characteristics of patients undergoing an initial hepatic resection for NELM, the operative details, pathological findings, and patient outcomes were investigated.

RESULTS

A total of 222 patients were enrolled from 30 institutions. The primary tumor site was the pancreas in 58.6%, and the presentation of NELM was synchronous in 63.1% of the cases. Concomitant resection of the primary tumor and liver metastases was performed for 66.4% of the synchronous metastases, and the 90-day morbidity and mortality rates were 12.6% and 0.9%, respectively. The operations resulted in R2 resections in 26.1% of the cases, and 83.4% of the patients experienced recurrence after R0/1 resections. However, the patients were treated using multiple modalities after R2 resection or recurrence, and the overall survival rate was relatively favorable, with 5-year and 10-year survival rates of 70.2%, and 43.4%, respectively. Univariable and multivariable analyses identified the tumor grading (G3) of the primary tumor as a significant prognostic factor for both the recurrence-free and overall survivals.

CONCLUSIONS

The present data confirmed the safety of the surgical resection of NELM. Although recurrences were frequent, the survival outcomes after resection were favorable when a multi-disciplinary treatment approach was used.

Distinctive features of pancreatic neuroendocrine neoplasms exhibiting an increment in proliferative activity during the course of the disease

PURPOSE

Neuroendocrine neoplasms (NENs) differ in their biological behavior and growth potential in a way that can be predicted using histological classification and grading systems. A subset of pancreatic NENs (pNENs) may develop a more aggressive phenotype during the course of the disease, associated with an increase in the Ki-67 proliferation index (PI). The purpose of the study was to present the clinical characteristics of these patients.

METHODS

Using re-biopsy of growing lesions, we investigated the increase in Ki-67 PI sufficient to change initial grading (G).

RESULTS

Of 264 patients with well differentiated (WD) pNENs who showed progressive disease during follow-up, 15 (6%) exhibited an increase in Ki-67 PI at a median time 36.8 (9.3-255.8) months. All neoplasms had WD-morphology: five had G1 (Ki-67 median value 1%), nine G2 (median value 5%), one G3 (25%) grades. Upon change of Ki-67 PI, 3 patients had G2 (8%) and 12 G3 (57.5%) NENs, while all retained their WD-morphology. At last follow-up, eight patients were alive with a median overall survival (OS) of 52.5 (9.5-264.3) months. Μedian OS was shorter in patients who had a change in Ki-67 PI before 36 months compared to those who had a change of Ki-67 PI at a later stage (27.5 95%CI: 11.88-43.06 vs. 120.87 95%CI: 96.05-145.69; log-rank p = 0.018).

CONCLUSIONS

During the course of their disease, 6% patients with progressive pNENs develop an increase in Ki-67 PI resulting in an increase in grading status while maintaining their morphology. This process is associated with worse OS when it occurs at an early stage.

Tumor Heterogenity in Gastro-Entero-Pancreatic Neuroendocrine Neoplasia

Owing to the rarity and the biological and clinical heterogeneity of gastroenteropancreatic neuroendocrine neoplasia (GEP NEN), the management of these patients may be challenging for physicians. This review highlights the specific features of GEP NEN with particular attention on the role of Ki67 heterogeneity, the potential prognostic role of novel radiological techniques, and the clinical usefulness of functional imaging, including 68Ga-DOTA-SST PET/CT and 18F-FDG PET/CT. Understanding these specific features may help to plan proper and tailored follow-up programs and therapeutic approaches.

Pathology Reporting in Neuroendocrine Neoplasms of the Digestive System: Everything You Always Wanted to Know but Were Too Afraid to Ask

During the 5th NIKE (Neuroendocrine tumors Innovation in Knowledge and Education) meeting, held in Naples, Italy, in May 2019, discussions centered on the understanding of pathology reports of gastroenetropancreactic neuroendocrine neoplasms. In particular, the main problem concerned the difficulty that clinicians experience in extrapolating relevant information from neuroendocrine tumor pathology reports. During the meeting, participants were asked to identify and rate issues which they have encountered, for which the input of an expert pathologist would have been appreciated. This article is a collection of the most rated questions and relative answers, focusing on three main topics: 1) morphology and classification; 2) Ki67 and grading; 3) immunohistochemistry. Patient management should be based on multidisciplinary decisions, taking into account clinical and pathology-related features with clear comprehension between all health care professionals. Indeed, pathologists require clinical details and laboratory findings when relevant, while clinicians require concise and standardized reports. In keeping with this last statement, the minimum requirements in pathology datasets are provided in this paper and should be a baseline for all neuroendocrine tumor professionals.

Modern therapeutic approaches for the treatment of malignant liver tumours

Malignant liver tumours include a wide range of primary and secondary tumours. Although surgery remains the mainstay of curative treatment, modern therapies integrate a variety of neoadjuvant and adjuvant strategies and have achieved dramatic improvements in survival. Extensive tumour loads, which have traditionally been considered unresectable, are now amenable to curative treatment through systemic conversion chemotherapies followed by a variety of interventions such as augmentation of the healthy liver through portal vein occlusion, staged surgeries or ablation modalities. Liver transplantation is established in selected patients with hepatocellular carcinoma but is now emerging as a promising option in many other types of tumour such as perihilar cholangiocarcinomas, neuroendocrine or colorectal liver metastases. In this Review, we summarize the available therapies for the treatment of malignant liver tumours, with an emphasis on surgical and ablative approaches and how they align with other therapies such as modern anticancer drugs or radiotherapy. In addition, we describe three complex case studies of patients with malignant liver tumours. Finally, we discuss the outlook for future treatment, including personalized approaches based on molecular tumour subtyping, response to targeted drugs, novel biomarkers and precision surgery adapted to the specific tumour.

CUX1-Transcriptional Master Regulator of Tumor Progression in Pancreatic Neuroendocrine Tumors

Recently, we identified the homeodomain transcription factor Cut homeobox 1 (CUX1) as mediator of tumour de-differentiation and metastatic behaviour in human insulinoma patients. In insulinomas, CUX1 enhanced tumour progression by stimulating proliferation and angiogenesis in vitro and in vivo. In patients with non-functional pancreatic neuroendocrine tumours (PanNET), however, the impact of CUX1 remains to be elucidated. Here, we analysed CUX1 expression in two large independent cohorts (n = 43 and n = 141 tissues) of non-functional treatment-naïve and pre-treated PanNET patients, as well as in the RIP1Tag2 mouse model of pancreatic neuroendocrine tumours. To further assess the functional role of CUX1, expression profiling of DNA damage-, proliferation- and apoptosis-associated genes was performed in CUX1-overexpressing Bon-1 cells. Validation of differentially regulated genes was performed in Bon-1 and QGP1 cells with knock-down and overexpression strategies. CUX1 expression assessed by a predefined immunoreactivity score (IRS) was significantly associated with shorter progression-free survival (PFS) of pre-treated PanNET patients (23 vs. 8 months; p = 0.005). In treatment-naïve patients, CUX1 was negatively correlated with grading and recurrence-free survival (mRFS of 39 versus 8 months; p = 0.022). In both groups, high CUX1 levels indicated a metastatic phenotype. Functionally, CUX1 upregulated expression of caspases and death associated protein kinase 1 (DAPK1), known as mediators of tumour progression and resistance to cytotoxic drugs. This was also confirmed in both cell lines and human tissues. In the RIP1Tag2 mouse model, CUX1 expression was associated with advanced tumour stage and resistance to apoptosis. In summary, we identified the transcription factor CUX1 as mediator of tumour progression in non-functional PanNET in vitro and in vivo, indicating that the CUX1-dependent signalling network is a promising target for future therapeutic intervention.

Achieving objective response in treatment of non-resectable neuroendocrine tumors does not predict longer time to progression compared to achieving stable disease

Background

There are several treatment modalities for unresectable neuroendocrine tumors. Traditionally, the aim of these treatments has been to reduce the tumor load; referred to as objective response (OR). Less emphasis has been put on inducing the tumors to stop growing without a reduction in total tumor load; termed as stable disease (SD). We wanted to investigate whether achieving OR compared to obtaining SD predicted a longer time to progression (TTP) in patients with neuroendocrine tumors (WHO Grade 1 and 2) treated with peptide receptor radionuclide therapy, chemotherapy or molecular targeted therapy.

Methods

Patients treated with either peptide receptor radionuclide therapy (PRRT) with ¹⁷⁷Lutetium-DOTA-octreotate, the chemotherapy combination streptozotocin/5-fluorouracil or everolimus were retrospectively assessed to evaluate the effect of the treatments on disease progression. We analyzed the TTP for patients for each treatment modality and compared the TTP between those who achieved OR and those who achieved SD.

Results

Altogether 56 patients treated with PRRT, 32 treated with streptozotocin/5-fluorouracil and 52 treated with everolimus were included in the analyses. The median TTP for those treated with PRRT and achieving OR was 31 months, the TTP for those achieving SD was 43 months (p = 0,2). For patients treated with streptozotocin/5-fluorouracil the results were: OR: 18 months, SD: 23 months (p = 0,9) and for those treated with everolimus; OR: 9 months, SD: 20 months (p = 0,5), respectively. We found no differences between patients achieving OR compared to SD regarding age, sex, stage, primary tumor location, Ki-67% or ongoing treatment with somatostatin analogues.

Conclusions

We found no treatment benefit with regard to TTP for our patients that experienced OR compared to those who achieved SD.

Resectable pancreatic solid lesions: Time to move from surgical diagnosis?

Benign or malignant conditions can present as pancreatic solid lesions (PSLs), and a thorough diagnostic workup is necessary to differentiate them. The need to acquire a tissue sample to reach a definitive diagnosis should be stratified by the findings at multidetector computed tomography (MDCT) with a pancreatic protocol. Tissue biopsy is currently indicated in patients fit for chemotherapy in whom a metastatic tumor or a locally advanced unresectable lesion are discovered. For these patients, EUS-guided tissue acquisition, with fine-needle aspiration (FNA) or biopsy represents the gold standard to provide a definitive cyto- and/or histopathologic diagnosis, with a high rate of accuracy. For resectable PSLs with a nonhypoenhancing MDCT pattern, which is not disease specific, a tissue diagnosis to distinguish benign from malignant etiologies appears mandatory. On the other hand, for hypo-enhancing PSLs, the debate of whether to obtain a preoperative definitive diagnosis still favors direct surgery. However, availability of novel EUS-guided fine-needle biopsy needles, which can ameliorate the negative predictive value of EUS-FNA and allow performance of DNA and RNA whole-genome extraction and RNA sequencing, coupled with the increasing evidence that preoperative neoadjuvant chemotherapy can be of value for these patients may change completely the diagnostic and therapeutic approach to resectable PSLs. These recent breakthroughs suggest the need for a new multidisciplinary consensus meeting to integrate them into the decision-making process assessing the need for preoperative tissue diagnosis in resectable PSLs.

Prognostic value of somatostatin receptor expressing tumor volume calculated from 68Ga-DOTATATE PET/CT in patients with well-differentiated neuroendocrine tumors

PURPOSE

To evaluate the prognostic value of volumetric parameters calculated from ⁶⁸Ga-1,4,7,10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid (DOTA)-Thr³-octreotate (⁶⁸Ga-DOTATATE) positron emission tomography/computed tomography (PET/CT) in patients with well-differentiated neuroendocrine tumor (WD-NET).

METHODS

Ninety-two patients (44 men and 48 women, mean age of 59.5-year-old) with pathologically confirmed WD-NET (grades 1 or 2) were enrolled in a prospective expanded access protocol. Selected data was analyzed retrospectively for this project. Maximum standardized uptake value (SUV_max) in the lesion with the highest ⁶⁸Ga-DOTATATE uptake was measured and recorded for each patient. In addition, two volumetric parameters, namely, somatostatin receptor expressing tumor volume (SRETV) and total lesion somatostatin receptor expression (TLSRE), were calculated in each ⁶⁸Ga-DOTATATE-avid lesion. SRETV was defined as tumor volume with higher ⁶⁸Ga-DOTATATE uptake than the 50% of SUV_max within the volume of interest (VOI) for each lesion. TLSRE was calculated by multiplying SRETV and mean SUV within the same VOI. Thereafter, the sum of SRETV (ΣSRETV) and TLSRE (ΣTLSRE) for all detected lesions per patient were calculated. Progression-free survival (PFS) was set as primary endpoint. Kaplan-Meier survival analysis, log-rank test, and Cox's proportional hazard model were used for statistical analysis.

RESULTS

Univariate analyses revealed significant difference of PFS for WHO tumor grade and ΣSRETV (P < 0.05), while there were no significant differences in age, sex, SUV_max, and ΣTLSRE (P > 0.05). Multivariate analysis identified WHO tumor grade and ΣSRETV as independent predictors of PFS.

CONCLUSION

ΣSRETV calculated from ⁶⁸Ga-DOTATATE PET/CT may have prognostic value of PFS in WD-NET patients.

FGD4 (Frabin) Overexpression in Pancreatic Neuroendocrine Neoplasms

OBJECTIVE

The pathogenesis of pancreatic neuroendocrine tumors (PNETs) is still unclear. We propose Frabin as a new molecular alteration in PNETs. Frabin is a guanine nucleotide exchange factor playing a role in mediating actin cytoskeleton changes during cell migration, morphogenesis, polarization, and division.

METHODS

Patients with PNETs of different grades were assessed for Frabin expression using immunohistochemistry and tissue microarray. The tissue microarray included 12 grade 1 and 3 grade 2 PNETs and 14 grade 3 pancreatic neuroendocrine carcinomas (PECAs). Frabin immunostain was scored with Allred system. Statistical analysis used SAS and R software. Immunohistochemistry scores were correlated with tumor grade and stage. The Spearman correlation coefficient was calculated with P values.

RESULTS

Pancreatic neuroendocrine tumors were graded according to the World Health Organization 2017 guidelines. Frabin was expressed by 24 (82.7%) of the PNET/PECA studied. Only 5 (17.2%) of the 29 PNETs/PECA evaluated were Frabin negative. Frabin expression was cytoplasmic in all cases. We found a significant positive correlation (ρ = 0.47) between Frabin immunohistochemistry score and tumor grade (P = 0.01). No correlation was found between Frabin expression and tumor stage (P = 0.91).

CONCLUSIONS

We report Frabin overexpression as a novel molecular alteration occurring in PNETs/PECAs.