Endocrinological Toxicity Secondary to Treatment of Gastroenteropancreatic Neuroendocrine Neoplasms (GEP-NENs)

Combined the surgery, radiation, and chemotherapy for predicting overall survival in patients with gastroenteropancreatic neuroendocrine tumors

BACKGROUND

Over the last few decades, the annual global incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has steadily increased. Because of the complex and inconsistent treatment of GEP-NETs, the prognosis of patients with GEP-NETs is still difficult to assess. The study aimed to construct and validate the nomograms included treatment data for prediction overall survival (OS) in GEP-NETs patients.

METHODS

GEP-NETs patients determined from the Surveillance, Epidemiology, and End Results (SEER)-13 registry database (1992-2018) and with additional treatment data from the SEER-18 registry database (1975-2016). In order to select independent prognostic factors that contribute significantly to patient survival and can be included in the nomogram, multivariate Cox regression analysis was performed using the minimum value of Akaike information criterion (AIC) and we analyzed the relationship of variables with OS by calculating hazard ratios (HRs) and 95% CIs. In addition, we also comprehensively compared the nomogram using to predict OS with the current 7th American Joint Committee on Cancer (AJCC) staging system.

RESULTS

From 2004 to 2015, a total of 42,662 patients at diagnosis years with GEP-NETs were determined from the SEER database. The results indicated that the increasing incidence of GEP-NETs per year and the highest incidence is in patients aged 50-54. After removing cases lacking adequate clinicopathologic characteristics, the remaining eligible patients (n=7,564) were randomly divided into training (3,782 patients) and testing sets (3,782 patients). In the univariate analysis, sex, age, race, tumor location, SEER historic stage, pathology type, TNM, stage, surgery, radiation, chemotherapy, and CS tumor size were found to be significantly related to OS. Ultimately, the key factors for predicting OS were determined, involving sex, age, race, tumor location, SEER historic stage, M, N, grade, surgery, radiation, and chemotherapy. For internal validation, the C-index of the nomogram used to estimate OS in the training set was 0.816 (0.804-0.828). For external validation, the concordance index (C-index) of the nomogram used to predict OS was 0.822 (0.812-0.832). In the training and testing sets, our nomogram produced minimum AIC values and C-index of OS compared with AJCC stage. Decision curve analysis (DCA) indicated that the nomogram was better than the AJCC staging system because more clinical net benefits were obtained within a wider threshold probability range.

CONCLUSION

A nomogram combined treatment data may be better discrimination in predicting overall survival than AJCC staging system. We highly recommend to use our nomogram to evaluate individual risks based on different clinical features of GEP-NETs, which can improve the diagnosis and treatment outcomes of GEP-NETs patients and improve their quality of life.

The Role of Somatostatin Analogues in the Control of Diarrhea and Flushing as Markers of Carcinoid Syndrome: A Systematic Review and Meta-Analysis

BACKGROUND

Somatostatin analogues (SSAs) are the cornerstone of treatment for carcinoid syndrome (CS)-related symptoms. The aim of this systematic review and meta-analysis is to evaluate the percentage of patients achieving partial (PR) or complete response (CR) with the use of long-acting SSAs in patients with CS.

METHODS

A systematic electronic literature search was conducted in PubMed, Cochrane, and Scopus to identify eligible studies. Any clinical trials reporting data on the efficacy of SSAs to alleviate symptoms in adult patients were considered as potentially eligible.

RESULTS

A total of 17 studies reported extractable outcomes (PR/CR) for quantitative synthesis. The pooled percentage of patients with PR/CR for diarrhea was estimated to be 0.67 (95% confidence interval (CI): 0.52-0.79, I₂ = 83%). Subgroup analyses of specific drugs provided no evidence of a differential response. With regards to flushing, the pooled percentage of patients with PR/CR was estimated to be 0.68 (95% CI: 0.52-0.81, I₂ = 86%). Similarly, no evidence of a significant differential response in flushing control was documented.

CONCLUSIONS

We estimate there is a 67-68% overall reduction in symptoms of CS associated with SSA treatment. However, significant heterogeneity was detected, possibly revealing differences in the disease course, in management and in outcome definition.

Efficacy, safety and unmet needs of evolving medical treatments for carcinoid syndrome

This review reports on the currently available medical treatment options for the control of symptoms due to carcinoid syndrome in patients with neuroendocrine tumors. The efficacy and adverse events (AEs) of approved drugs such as somatostatin analogues (SSA), telotristat ethyl (TE) and interferon-alpha, are reviewed. Somatostatin analogues remain the standard treatment of carcinoid syndrome based on the high expression of somatostatin receptors and the resulting inhibition of secretion of bioactive compounds; their use is associated with relatively mild AEs, involving mainly the gastrointestinal system, and being usually transient. Although dose escalation of SSA remains an unapproved option, it is clinically implemented to alleviate symptoms in refractory carcinoid syndrome and supported by the most recent guidelines. The side effects associated with the increased dose are in general mild and consistent with standard dose of SSA. Telotristat ethyl, an oral inhibitor of tryptophan hydroxylase, the rate-limiting enzyme in serotonin biosynthesis, represents a rather novel innovative treatment option in patients with carcinoid syndrome suffering from diarrhea and complements the standard therapy of SSA. Given the low toxicity profile, TE may be considered an early add-on treatment to SSA in patients with uncontrolled carcinoid syndrome. However, further prolonged follow-up of patients treated with TE may be needed to exclude potential AEs, such as liver toxicity or depressed mood, in patients with long-term treatment. Interferon alpha is a cytokine with direct inhibitory effect on hormone secretion and tumor cell proliferation and an approved therapy in carcinoid syndrome but is associated with significant AEs in the majority of the patients requiring frequently dose reduction. The finding of a more favorable tolerability of pegylated interferon needs to be confirmed in a prospective study.

TCF-3-mediated transcription of lncRNA HNF1A-AS1 targeting oncostatin M expression inhibits epithelial-mesenchymal transition via TGFβ signaling in gastroenteropancreatic neuroendocrine neoplasms

Long noncoding RNAs play key roles in several cancers, but their potential functions in gastroenteropancreatic neuroendocrine neoplasms remain to be investigated. We performed GeneChip assay to explore differentiated lncRNAs in gastric NENs and peri-cancerous tissues. The regulation of HNF1A-AS1 on biological behavior of GEP-NENs cells and in vivo xenograft model was confirmed by CCK8, colony formation assay, transwell, western blot and qRT-PCR. We next detected the potential transcription factors and the binding sites between them with bioinformatic analysis. qRT-PCR was performed to analyze the exact relationship between them. HNF1A-AS1 expression was decreased in gastric NENs tissues (p < 0.01). Over-expression of HNF1A-AS1 suppressed cellular proliferation, migration and invasion. Knockdown of transcription factor 3 inhibited the expression of HNF1A-AS1 and promoted cellular migration and invasion. Oncostatin M was identified as the downstream target of HNF1A-AS1. Inhibition of transforming growth factor-β activity inhibited HNF1A-AS1/Oncostatin M-mediated epithelial-mesenchymal transition. Our data suggest that transcription factor 3/HNF1A-AS1/Oncostatin M axis inhibits the tumorigenesis and metastasis of gastroenteropancreatic neuroendocrine neoplasms via transforming growth factor-β signaling.

Cardiovascular Toxicities Secondary to Biotherapy and Molecular Targeted Therapies in Neuroendocrine Neoplasms: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials

A broad spectrum of novel targeted therapies with prime antitumor activity and/or ample control of hormonal symptoms together with an overall acceptable safety profile have emerged for patients with metastatic neuroendocrine neoplasms (NENs). In this systematic review and quantitative meta-analysis, the PubMed, EMBASE, Cochrane Central Register of Controlled Trials and clinicaltrials.gov databases were searched to assess and compare the safety profile of NEN treatments with special focus on the cardiovascular adverse effects of biotherapy and molecular targeted therapies (MTTs). Quality/risk of bias were assessed using GRADE criteria. Placebo-controlled randomized clinical trials (RCTs) in patients with metastatic NENs, including medullary thyroid cancer (MTC) were included. A total of 3695 articles and 122 clinical trials registered in clinicaltrials.gov were screened. We included sixteen relevant RCTs comprising 3408 unique patients assigned to different treatments compared with placebo. All the included studies had a low risk of bias. We identified four drug therapies for NENs with eligible placebo-controlled RCTs: somatostatin analogs (SSAs), tryptophan hydroxylase (TPH) inhibitors, mTOR inhibitors and tyrosine kinase inhibitors (TKI). Grade 3 and 4 adverse effects (AE) were more often encountered in patients treated with mTOR inhibitors and TKI (odds ratio [OR]: 2.42, 95% CI: 1.87-3.12 and OR: 3.41, 95% CI: 1.46-7.96, respectively) as compared to SSAs (OR:0.77, 95% CI: 0.47-1.27) and TPH inhibitors (OR:0.77, 95% CI: 0.35-1.69). MTOR inhibitors had the highest risk for serious cardiac AE (OR:3.28, 95% CI: 1.66-6.48) followed by TKIs (OR:1.51, 95% CI: 0.59-3.83). Serious vascular AE were more often encountered in NEN patients treated with mTOR inhibitors (OR: 1.72, 95% CI: 0.64-4.64) and TKIs (OR:1.64, 95% CI: 0.35-7.78). Finally, patients on TKIs were at higher risk for new-onset or exacerbation of pre-existing hypertension (OR:3.31, 95% CI: 1.87-5.86). In conclusion, SSAs and TPH inhibitors appear to be safer as compared to mTOR inhibitors and TKIs with regards to their overall toxicity profile, and cardiovascular toxicities in particular. Special consideration should be given to a patient-tailored approach with anticipated toxicities of targeted NEN treatments together with assessment of cardiovascular comorbidities, assisting clinicians in treatment selection and early recognition/management of cardiovascular toxicities. This approach could improve patient compliance and preserve cardiovascular health and overall quality of life.

Occurrence of exocrine pancreatic insufficiency in patients with advanced neuroendocrine tumors treated with somatostatin analogs

BACKGROUND

Although exocrine pancreatic insufficiency (EPI) has been described in patients with neuroendocrine neoplasia (NEN) treated with somatostatin analogs (SSAs), its role in the therapeutic management of these patients is not well established.

AIM

To determine the frequency of EPI in patients with NEN long-term treated with SSAs.

METHODS

This is a prospective single-center study evaluating 35 patients treated with SSAs for >12 months due to unresectable/advanced nonpancreatic well-differentiated NEN. Clinical evaluation, biochemical parameters, and fecal elastases 1 (FE-1) were assessed to diagnose EPI.

RESULTS

A total of 7 patients (20%) had EPI, given the presence of abdominal symptoms and a median FE-1 value of 180 mcg/g stool (150-198). No patient had severe EPI, defined as FE-1 < 100 mcg/g stool. Elevated glycated Hb levels were a significant predictor for developing EPI (OR 4.81, p = 0.01). No significant difference in terms of duration of SSA treatment was observed between patients with or without EPI diagnosed (84 months and 72 months, respectively; p = 0.950).

CONCLUSIONS

Mild-moderate EPI is a relatively common condition in patients receiving long-term treatment with SSAs. Specific clinical and biochemical evaluations, including FE-1, should be planned in these patients to diagnose this relevant condition early, which may deteriorate quality of life and cause malnutrition.