Identifying Prognostic Factors for Well-Differentiated Metastatic Pancreatic Neuroendocrine Tumours: A Retrospective International Multicentre Cohort Study

Reconsideration of Clinicopathologic Prognostic Factors in Pancreatic Neuroendocrine Tumors for Better Determination of Adverse Prognosis

The question of how successful we are in predicting pancreatic neuroendocrine tumors (panNET) with poor prognosis has not been fully answered yet. The aim of this study was to investigate the effects of clinicopathological features on prognosis and to determine their validity in prediction of prognosis and whether a better prognostic classification can be made. Fifty-six patients who underwent pancreatic resection for pancreatic neuroendocrine tumor were included. The associations between clinicopathological parameters and prognosis were evaluated statistically. Efficiencies of different thresholds for tumor size, mitotic count, and Ki67 proliferation index for prognosis prediction were compared. Vascular invasion was statistically associated with high tumor grade, advanced pT stage, and mortality rate. The presence of non-functional tumor, lymphatic invasion, and > 10 cm tumor size were significantly related to shorter overall survival. Advanced pT stage (pT3-4), > 5 cm tumor size, and high tumor grade (grades 2-3) were significantly associated with shorter disease-free survival. The mortality rate showed the strongest statistical significance with mitotic count when grouped as 1: < 2, 2: 2-10, and 3: > 10 mitosis/ 2 mm². The 10% threshold value for Ki67 index was more successful in predicting adverse prognosis. Among the morphologic variants, the ductulo-insular variant was the most promising to have positive prognostic value in our series, although no statistical significance was detected. In conclusion, threshold values of 5 cm and 10 cm for tumor size, 10% for Ki67 proliferation index, and 10/2 mm² for mitotic count and vascular and lymphatic invasion assessed separately are potential prognostic candidates for better stratification of panNETs.

Bone Metastases in Neuroendocrine Tumors: Molecular Pathogenesis and Implications in Clinical Practice

Skeletal colonization is often regarded as a rare event in patients with neuroendocrine tumors (NETs) although both national registries and retrospective series report an incidence of bone metastases as high as 20% in subjects with advanced disease. While the biological mechanisms leading to bone metastatic colonization in NETs have been poorly investigated so far, key steps of osteotropic mechanisms, including the epithelial-to-mesenchymal transition, preparation of the premetastatic niche, migration of circulating tumor cells towards the bone marrow as well as the resulting alterations of the skeletal metabolism, are likely to operate also during the development of NET bone metastases. The skeleton involvement by NETs has a detrimental impact on both quality of life and patients' prognosis, leading to pain in the majority of symptomatic subjects. While it is currently unclear whether or not the earlier recognition of bone involvement by PET/CT imaging techniques employing 68Ga-DOTA-conjugated peptides might improve outcomes through the exploitation of timely treatments, the management of bone-colonizing NETs is today based only on clinical experience from other osteotropic tumors. Here, we summarize the fundamental molecular mechanisms driving bone colonization and revisit both established and novel treatments for patients with bone metastatic NETs.

Sequence of therapy and survival in patients with advanced pancreatic neuroendocrine tumours

Background

Pancreatic neuroendocrine tumours (pnets) often present as advanced disease. The optimal sequence of therapy is unknown.

Methods

Sequential patients with advanced pnets referred to BC Cancer between 2000 and 2013 who received 1 or more treatment modalities were reviewed, and treatment patterns, progression-free survival (pfs), and overall survival (os) were characterized. Systemic treatments included chemotherapy, small-molecule therapy, and peptide receptor radionuclide therapy.

Results

In 66 cases of advanced pnets, median patient age was 61.2 years (25%-75% interquartile range: 50.8-66.2 years), and men constituted 47% of the group. First-line therapies were surgery (36%), chemotherapy (33%), and somatostatin analogues (32%). Compared with first-line systemic therapy, surgery in the first line was associated with increased pfs and os (20.6 months vs. 6.3 months and 100.3 months vs. 30.5 months respectively, p < 0.05). In 42 patients (64%) who received more than 1 line of therapy, no difference in os or pfs between second-line therapies was observed.

Conclusions

Our results confirm the primary role of surgery for advanced pnets. New systemic treatments will further increase options.

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.

Effect of metastatic site on survival in patients with neuroendocrine neoplasms (NENs). An analysis of SEER data from 2010 to 2014

BACKGROUND

Neuroendocrine neoplasms (NENs) display variable behaviors based on origin and grade. We assumed that both tumor origin and the location of metastasis may play a role in survival.

METHODS

We queried the SEER database (2010-2014) for patients with an established diagnosis of NENs and documented site of metastasis and identified 2005 patients. Overall survival (OS) at the time points were estimated by the Kaplan-Meier method Cox proportional-hazards models were used to evaluate the relationship of the interested variables and OS.

RESULTS

Lung, liver, bone and brain metastases were observed in 9, 77, 7 and 6% of metastatic patients respectively. In the multivariate model, metastasis locations were significantly associated with worse survival (liver HR: 1.677 (1.226-2.294); (bone metastasis HR: 1.412 (0.965-2.065); brain HR: 1.666 (1.177-2.357)). We produced a scoring system based on site of origin, metastasis location, age, gender, histology and tumor size that can stratify metastatic NEN patients in low, intermediate and high-risk categories to help physicians with decision making.

CONCLUSION

Site of metastasis plays an important role in survival of metastatic NEN patients independent of commonly described prognostic factors and should be considered in survival estimates.

Impact of liver tumour burden, alkaline phosphatase elevation, and target lesion size on treatment outcomes with 177Lu-Dotatate: an analysis of the NETTER-1 study

PURPOSE

To assess the impact of baseline liver tumour burden, alkaline phosphatase (ALP) elevation, and target lesion size on treatment outcomes with ¹⁷⁷Lu-Dotatate.

METHODS

In the phase 3 NETTER-1 trial, patients with advanced, progressive midgut neuroendocrine tumours (NET) were randomised to 177Lu-Dotatate (every 8 weeks, four cycles) plus octreotide long-acting release (LAR) or to octreotide LAR 60 mg. Primary endpoint was progression-free survival (PFS). Analyses of PFS by baseline factors, including liver tumour burden, ALP elevation, and target lesion size, were performed using Kaplan-Meier estimates; hazard ratios (HRs) with corresponding 95% CIs were estimated using Cox regression.

RESULTS

Significantly prolonged median PFS occurred with ¹⁷⁷Lu-Dotatate versus octreotide LAR 60 mg in patients with low (< 25%), moderate (25-50%), and high (> 50%) liver tumour burden (HR 0.187, 0.216, 0.145), and normal or elevated ALP (HR 0.153, 0.177), and in the presence or absence of a large target lesion (diameter > 30 mm; HR, 0.213, 0.063). Within the ¹⁷⁷Lu-Dotatate arm, no significant difference in PFS was observed amongst patients with low/moderate/high liver tumour burden (P = 0.7225) or with normal/elevated baseline ALP (P = 0.3532), but absence of a large target lesion was associated with improved PFS (P = 0.0222). Grade 3 and 4 liver function abnormalities were rare and did not appear to be associated with high baseline liver tumour burden.

CONCLUSIONS

¹⁷⁷Lu-Dotatate demonstrated significant prolongation in PFS versus high-dose octreotide LAR in patients with advanced, progressive midgut NET, regardless of baseline liver tumour burden, elevated ALP, or the presence of a large target lesion. Clinicaltrials.gov : NCT01578239, EudraCT: 2011-005049-11.

The Value of Alkaline Phosphatase-to-Albumin Ratio in Detecting Synchronous Metastases and Predicting Postoperative Relapses among Patients with Well-Differentiated Pancreatic Neuroendocrine Neoplasms

Backgrounds

Pancreatic neuroendocrine neoplasm (pNEN) is a highly heterogeneous entity, presenting widely varied biological behavior as well as long-term prognosis. Reliable biomarkers are urgently needed to make risk stratifications for pNEN patients, which could be beneficial to the development of individualized therapeutic strategy in the clinical practice. Here, we aimed to evaluate the predictive and prognostic roles of serum alkaline phosphatase-to-albumin ratio (APAR) in well-differentiated pNEN patients.

Methods

We retrospectively analyzed the pathologically confirmed grade 1/2 pNEN patients, who were originally treated in our hospital from February 2008 to April 2018. Univariate and multivariate analyses were performed to assess the value of APAR in detecting synchronous metastases and predicting relapses following curative resections.

Results

A total of 170 eligible cases were included into analysis. Logistic univariate analysis indicated APAR (P=0.002) was significantly associated with synchronous distant metastasis among well-differentiated pNEN patients, which was further demonstrated to be an independent risk factor by multivariate analysis (odds ratio 8.127, 95% confidence interval (CI) 2.105–31.372, P=0.002) was significantly associated with synchronous distant metastasis among well-differentiated pNEN patients, which was further demonstrated to be an independent risk factor by multivariate analysis (odds ratio 8.127, 95% confidence interval (CI) 2.105–31.372, P=0.002) was significantly associated with synchronous distant metastasis among well-differentiated pNEN patients, which was further demonstrated to be an independent risk factor by multivariate analysis (odds ratio 8.127, 95% confidence interval (CI) 2.105–31.372, P=0.002) was significantly associated with synchronous distant metastasis among well-differentiated pNEN patients, which was further demonstrated to be an independent risk factor by multivariate analysis (odds ratio 8.127, 95% confidence interval (CI) 2.105–31.372, P=0.002) was significantly associated with synchronous distant metastasis among well-differentiated pNEN patients, which was further demonstrated to be an independent risk factor by multivariate analysis (odds ratio 8.127, 95% confidence interval (CI) 2.105–31.372,

Conclusion

APAR may work as a convenient pretreatment marker to detect synchronous distant metastasis for well-differentiated pNEN patients and predict recurrences for curatively resected cases without nerve or vascular invasion. However, these findings should be further verified in prospectively well-designed studies.

Brain metastases in patients with neuroendocrine neoplasms: risk factors and outcome

Background

Brain metastases (BM) are rarely reported in patients with neuroendocrine carcinoma (NEC) of non-lung origin and neuroendocrine tumors (NET) of the gastroenteropancreatic (GEP) or bronchopulmonary system. However, symptomatic brain metastases are associated with dismal prognosis, so early detection and treatment could be advisable.

Methods

We retrospectively analyzed 51 patients with GEP-NEN and bronchopulmonary NEN excluding small cell lung cancer. All patients were treated at the University Hospital Marburg and Halle (Saale) between 2000 and 2017. The median overall survival (mOS) and mOS after diagnosis of brain metastases (BM) were calculated using Kaplan-Meier analysis. Risk factors for poor prognosis were evaluated using univariate and multivariate Cox regression method.

Results

Overall, 51 patients with a median age of 58 years presented BM. Lung (n = 23, 45.1%) was the most frequent primary localization. Most patients had NEC (n = 31, 60.8%), including 26 carcinomas (51%) with Ki-67 indices > 55%. Singular BM were present in 16 patients (31.4%), but 21 patients (41.2%) had multiple lesions. Overall, the median period from first diagnosis of the tumor disease up to diagnosis of brain metastasis was 5.0 months. Palliative radiation was the most common therapy (n = 31, 60.8%). Median OS after initial diagnosis and diagnosis of BM was 23.0 and 11.0 months, respectively. Univariate and multivariate analysis for prognostic indicators depicted differentiation (NEC HR 4.2, 95% CI 1.1–16.1) and age (≥60 HR 3.0, 95% CI 1.2–7.5) as markers for poor outcome.

Conclusions

Overall, the risk for symptomatic brain metastases is low in GEP-NEN and bronchopulmonary NEN patients. Age above 60 and poor tumor differentiation may deteriorate the overall survival. Therefore, screening for brain metastases could be advisable in NEC patients.