Metastatic Gastroenteropancreatic Neuroendocrine Tumors Research Articles

Abstract 7614: Mutations in MEN1/DAXX/ATRX are associated with improved progression-free survival in patients with gastroenteropancreatic neuroendocrine tumors receiving peptide receptor radionuclide therapy

Abstract Background: Peptide Receptor Radionuclide Therapy (PRRT) using 177Lu-DOTATATE is an effective treatment for metastatic Gastroenteropancreatic Neuroendocrine Tumors (GEP-NETs). However, it remains unknown why some patients (pts) respond more favorably than others. Pre-clinical data suggests that mutations in the MEN1, DAXX, and/or ATRX genes influence DNA repair capabilities and increase radiation effect in cancer cells. We therefore thought to evaluate the association between response to PRRT and the presence of MEN1, DAXX, and/or ATRX mutations in patients with GEP-NETs. Methods: We retrospectively analyzed CLIA certified tissue-based Next Generation Sequencing (NGS) assay results and clinicopathological data from 28 pts with GEP-NETs treated with PRRT at our center from 2017 to 2023. Genetic findings were correlated with progression-free survival (PFS) using Kaplan-Meier estimators and Cox proportional hazards regression modeling. Objective response was assessed per RECIST v1.1 by investigator review. Results: Pts with mutations in MEN1, DAXX, or ATRX (n = 13, 46.42%) had a longer PFS [mPFS, 26.47 months (95% CI, 17.97 - NA) vs. 12.13 months (95% CI, 9.17 - NA); HR, 0.19; 95% CI, 0.06 - 0.68; p = 0.01] than wildtype (n = 15, 53.58%) pts, when adjusted for surgery prior to PRRT and tumor grade. Pts with mutations in MEN1 along with a concurrent mutation in either DAXX or ATRX (n = 6) trended towards better PFS compared to patients without concurrent mutations [only MEN1mt or DAXXmt/ATRXmt, but not both; mPFS, 31.53 months (95% CI, 28.43 - NA) vs. 17.97 months (95% CI, 11.17 - NA); HR, 0.25; 95% CI, 0.05 - 1.29; p = 0.09]. Among evaluable pts, objective response rate was higher in pts with a mt in MEN1, DAXX, or ATRX compared to wild-type pts (41.67% vs. 15.38%; p = 0.09). In the pancreatic NET (PNET) subset, mutations in either MEN1, DAXX, or ATRX were found in 11/16 pts (68.75%) and were also associated with a better PFS compared to wild type patients [mPFS, 28.43 months (95% CI, 11.50 - NA) vs. 9.83 months (95% CI, 7.83 - NA); HR, 0.21; 95% CI, 0.05 - 0.95; p = 0.04). Conclusions: Mutations in MEN1/DAXX/ATRX correlate with improved PFS in patients with GEP-NETs receiving PRRT. Concurrent mutations in MEN1 and DAXX/ATRX may have additive effects on response to PRRT. If validated in larger studies, these findings may represent a novel biomarker to predict PRRT response. Limitations: Limited sample size precludes generalization of results and might overestimate effect sizes. Citation Format: Rushabh Gujarathi, Sara Abou Azar, Joseph Tobias, Xavier Keutgen, Chih-Yi Liao. Mutations in MEN1/DAXX/ATRX are associated with improved progression-free survival in patients with gastroenteropancreatic neuroendocrine tumors receiving peptide receptor radionuclide therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7614.

177 Lu-DOTATATE Salvage Therapy in Rapidly Progressing Neuroendocrine Tumor With Poor Performance Status.

Peptide receptor radionuclide therapy (PRRT) has shown to be effective and safe in metastatic gastroenteropancreatic and nongastroenteropancreatic neuroendocrine tumors. However, the selection criteria for PRRT are restricted to patients with good performance status (Eastern Cooperative Oncology Group score ≤2 or Karnofsky performance score ≥60). This denies many patients with adequate somatostatin receptor expression and biochemical profiles from the beneficial effects of PRRT on the quality of life, daily function, and overall survival. The 2 cases highlight the favorable response of PRRT in patients with metastatic neuroendocrine tumor having a very poor performance status initially.

Surgical cytoreduction vs systemic therapy in patients with metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETS): NCDB analysis

Surgical cytoreduction vs systemic therapy in patients with metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETS): NCDB analysis

Clinical impact of unsuccessful subcutaneous administration of octreotide LAR instead of intramuscular administration in patients with metastatic gastroenteropancreatic neuroendocrine tumors.

Octreotide LAR is a long-acting somatostatin analogue (SSA) used in the management of metastatic gastroenteropancreatic neuroendocrine tumors (GEP NETs). It requires intramuscular (IM) injection. Missed IM injections cause subcutaneous nodules (SCNs) on radiologic images. We reviewed the rates of SCNs in a real-world cohort of GEP NETs receiving octreotide LAR and explored treatment outcomes. Patients commencing octreotide LAR between August 5, 2010 and March 8, 2018 at a single cancer center in Canada were identified from pharmacy records. Patients were included if they had a computed tomography (CT) scan performed at the time of progression and a preceding CT with pelvis included to enable assessment for the presence of nodules. Fisher's exact test was used to examine predictors of SCNs, and Kaplan-Meier curves summarized differences in progression free (PFS) and overall survival (OS) that were compared with log-rank tests. Of 243 patients receiving octreotide LAR, 45 had all required CT images available for central review. SCNs were found in 20/45 (44%) of patients on the last scan showing stable disease before progression and were numerically but not statistically more likely in females (OR: 2.36, 95% CI: 0.66-8.29, p = .23). There was an increased risk of SCNs in patients with a skin-to-muscle distance >38 mm (the length of an octreotide LAR needle) on CT (OR: 5.09, 95% CI: 1.39-16.6, p = .018) and a trend toward increased risk in obese patients (OR: 5.71, 95% CI: 1.26-23.4, p = .061). PFS (HR: 1.01, 95% CI: 0.56-1.78, p = .98) and OS (HR: 0.86, 95% CI: 0.41-1.8, p = .70) was similar between those with/without SCNs. In conclusion, almost half of patients receiving octreotide LAR had SCNs; however, missed administration of SSA did not appear to result in worse survival in this small study. Factors such as sex, younger age skin-to-muscle distance, and obesity may affect SCN development and should be considered when choosing an SSA.

Experience with 177Lu-Dotatate in Patients with Metastatic Gastroenteropancreatic Neuroendocrine Tumors at a Single Urban Cancer Center

177Lu-Dotatate is an FDA approved peptide receptor radiotherapeutic (PRRT) agent for metastatic well differentiated midgut neuroendocrine tumors (NETs). Questions remain regarding tolerability in diverse subpopulations with higher grade disease, more than one prior line of treatment, and in non-ileal primaries. In this retrospective analysis, we review the outcomes of patients with histologically proven metastatic GEP-NETs who received 177Lu-Dotatate at a single racially diverse urban cancer center. Treated patients had disease that progressed on systemic therapy. Uptake at disease sites was demonstrated in all patients using 68-Gallium-Dotate PET/CT. ECOG performance score (PS) was 0 to 2. 177Lu-Dotatate was administered in 200 mCi doses every 8 weeks for a total of 4 cycles and a maximum of 800 mCi. Patients were followed with serial CT scan and/or abdominal MRI with best objective response assessed per RECIST criteria. Fifty-one patients were treated between December 2017 and September 2021. 42 patients completed a minimum 3-month follow-up imaging. Median age was 66 years, 59% were female, 66% identified as white, 26% as Black, 8% as other or chose not to specify. Most frequent primary site was small intestine (69%). All had metastatic disease involving the liver except for one. Median time from diagnosis to 177Lu-Dotatate was 51 months. Time from first line therapy to first 177Lu-Dotatate was 3.65 years CTCAE grade 3/4 hematologic toxicity was seen in 6 of 51 patients (12%) of patients. Grade 3/4 thrombocytopenia occurred in 3 pts, grade 3/4 leukopenia occurred in 2 pts and grade 3 anemia occurred in 1 patient. One patient developed myelodysplastic syndrome 1 year after first 177Lu-Dotatate. Patients who identified as non-white did not experience significantly higher rate of toxicity. Of the 42 patients who reached 3-month follow-up 29% had a partial response, 45% had a mixed or stable response, and 36% had progressive disease. Only gender demonstrated significant difference; with male gender associated with worse response categories (p = 0.001). Median overall survival (OS) was 2.13 years. Metastatic disease in the liver only (p = 0.013), tumor grade > 1 (p = 0.027), and no history of surgery (p = 0.011) were associated with significantly worse OS. The median progression free survival (PFS) was 1.56 years. Patients of male gender (p = 0.037), with liver only metastases (p = 0.013), and with higher grade tumors (p = 0.024) had worse PFS. There was no difference in PFS by race, primary tumor site (pancreatic vs small bowel), performance status, or prior treatment history. In this retrospective study, investigating a racially and socioeconomically diverse patients, we report similar toxicity to prior studies investigating 177Lu-Dotatate. Despite similar toxicity, median PFS and OS were inferior to reported outcomes in NETTER-1 which we suspect may be partly due to timing of treatment and differences in patient populations.

Systemic Therapy for Tumor Control in Metastatic Well-Differentiated Gastroenteropancreatic Neuroendocrine Tumors: ASCO Guideline.

To develop recommendations for systemic therapy for well-differentiated grade 1 (G1) to grade 3 (G3) metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs). ASCO convened an Expert Panel to conduct a systematic review of relevant studies and develop recommendations for clinical practice. Eight randomized controlled trials met the inclusion criteria for the systematic review. Somatostatin analogs (SSAs) are recommended as first-line systemic therapy for most patients with G1-grade 2 (G2) metastatic well-differentiated GI-NETs. Observation is an option for patients with low-volume or slow-growing disease without symptoms. After progression on SSAs, peptide receptor radionuclide therapy (PRRT) is recommended as systematic therapy for patients with somatostatin receptor (SSTR)-positive tumors. Everolimus is an alternative second-line therapy, particularly in nonfunctioning NETs and patients with SSTR-negative tumors. SSAs are standard first-line therapy for SSTR-positive pancreatic (pan)NETs. Rarely, observation may be appropriate for asymptomatic patients until progression. Second-line systemic options for panNETs include PRRT (for SSTR-positive tumors), cytotoxic chemotherapy, everolimus, or sunitinib. For SSTR-negative tumors, first-line therapy options are chemotherapy, everolimus, or sunitinib. There are insufficient data to recommend particular sequencing of therapies. Patients with G1-G2 high-volume disease, relatively high Ki-67 index, and/or symptoms related to tumor growth may benefit from early cytotoxic chemotherapy. For G3 GEP-NETs, systemic options for G1-G2 may be considered, although cytotoxic chemotherapy is likely the most effective option for patients with tumor-related symptoms, and SSAs are relatively ineffective. Qualifying statements are provided to assist with treatment choice. Multidisciplinary team management is recommended, along with shared decision making with patients, incorporating their values and preferences, potential benefits and harms, and other characteristics and circumstances, such as comorbidities, performance status, geographic location, and access to care.Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines.

Systemic Therapy for Tumor Control in Well-Differentiated Metastatic Gastroenteropancreatic Neuroendocrine Tumors: ASCO Guideline Q and A.

ASCO recently published new guidance on systemic therapy for tumor control in well-differentiated metastatic gastrointestinal and pancreatic neuroendocrine tumors in the Journal of Clinical Oncology. A companion Q and A article in the JCO-OP addresses some of the questions that clinicians may face as they implement these recommendations into clinical practice, including the role of somatostatin receptors and observation, definition of terms used within the guideline, considerations related to therapy options for G3 NETs, and future direction in research and treatment. ASCO also plans to address recommendations on the topic of symptom control of GEP-NETs in a forthcoming guideline

The NETFIT trial: Smart wearable medical devices to assess the quality of life of patients with metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NET).

e13627 Background: Patients diagnosed with an advanced NET are frequently deteriorating their quality of life due to tumor volume, hormone-release related symptoms and treatment toxicity. Changes on lifestyle of patients with solid tumors have shown an improvement in quality of life. However, NET patients are missed in those studies. Methods: We conducted a prospective, multicenter, observational study that included 40 patients with advanced NETs from 10 Spanish hospitals belonging to the Spanish Taskforce Group of Neuroendocrine and Endocrine Tumors (GETNE). The aim of the trial was to assess and monitor changes on different aspects in quality of life by a customized smartphone app linked to an activity wearable tracker. Data were analyzed at baseline and monthly for 16 weeks after physical activity, sleep and nutritional intervention. The primary objective was to evaluate improvement in the quality of life of patients with metastatic G1 and G2 GEP-NETs based on changes registered on the EORTC QOL-C30-GI.NET21 questionnaire during the first 16 weeks since the onset of an active systemic treatment with somatostatin analogs. Secondary endpoints included description of changes in physical exercise and sleep variables from baseline, as well as the evaluation of functional scales in patients with or without carcinoid syndrome. Results: A total of 40 patients were included in the study and all quality of life questionnaires were collected from week 0 to week 16 from 25 patients. In 15 patients there was a lack of compliance filling the questionnaires. All of the 25 patients analyzed experienced an improvement in at least one of the items of the QOL-C30 questionnaires of the primary endpoint after the first 16 weeks. As secondary outcomes it was shown a trend towards an improvement in vital signs, such as decrease in systolic blood pressure (median W0:130.7mmHg to W16:124.3mmHg p=0.3), diastolic (W0:88.7mmHg vs W16:83.3mmHg p=0.4) and heart rate (W0:93.3bpm vs W16:86bpm p=0.25). In addition, an improvement in sleep quality was observed, measured by the amount of deep REM sleep (W0:102.59 vs W16:115.3 median min/day p=0.31) or periods of light non-REM sleep (W0:301,43 vs W16:341,1 median min/day p=0.21). In the EORTC QLQ-C30 questionnaire, an improvement was observed in all functional scales (emotional function mean functional improvement (MFI) 5.3 (p=0.2), cognitive function MFI 4.0 (p=0.27), social function MFI 6.0 (p=0.3)), being deeply significant in role function (MFI 13.3 points; p=0.0156). There was an improvement in the symptomatology scales between W0 and W16, fatigue -3.7 p=0.3, nausea -1.3 p=0.5, pain -2.5 p=0.3, insomnia -9.7 p=0.05, anorexia -2.7 p= 0.3, diarrea -17.3 p=0.01. Conclusions: NETFIT trial showed that lifestyle intervention has a significant impact on the quality of life and symptomatic control of patients with metastatic G1/2 GEP-NETs.

The impact of surgery and survival prediction in patients with gastroenteropancreatic neuroendocrine tumors: a population-based cohort study.

This study aimed at assessing the impact of surgical treatments in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs). A propensity score-matched analysis based on data in the Surveillance, Epidemiology, and End Results database was used to assess the efficacy of surgical treatment in patients with GEP-NETs. A total of 7515 patients diagnosed with GEP-NETs from 2004 to 2015 were evaluated from the Surveillance, Epidemiology, and End Results database. There were 1483 patients in the surgery group and 6032 patients in the nonsurgery group. Compared with patients in the surgery group, patients in the nonsurgery group were inclined to receive chemotherapy (50.8 vs. 16.7%) and radiation (12.9 vs. 3.7%) as treatment options. Multivariate Cox regression analysis revealed higher rates of overall survival (OS) outcomes for GEP-NETs patients who had been subjected to surgery (hazard ratio=0.483, 95% CI=0.439-0.533, P <0.001). Then, to reduce the impact of bias, a 1:1 propensity score-matched analysis was performed for the two groups of patients. A total of 1760 patients were assessed and each subgroup included 880 patients. In the matched population, the patients exhibited the ability to significantly benefit from surgery (hazard ratio=0.455, 95% CI=0.439-0.533, P <0.001). The OS outcomes for radiation or chemotherapy patients who had been treated with surgery were better than those of patients who had not been treated with surgery ( P <0.001). In addition, it was found that the OS of patients was not significant after rectum and small intestine surgery, whereas there was a significant difference in OS after colon, pancreas, and stomach surgery on the patients. Patients who had been subjected to surgery in the rectum and small intestines exhibited better therapeutic benefits. Patients with GEP-NETs who are treated with surgery have better OS outcomes. Therefore, surgery is recommended for specified selected patients with metastatic GEP-NETs.

Outcome analysis in patients with metastatic gastroenteropancreatic neuroendocrine tumors receiving peptide receptor radionuclide therapy with Lu-177-DOTATATE.

Patients with neuroendocrine tumors (NET) of the gastroenteropancreatic tract (GEP-NET) were effectively treated with peptide receptor radionuclide therapy (PRRT) with Lu-177-DOTATATE in the NETTER-1 trial. The aim of this study was to assess the outcome of metastatic GEP-NET patients within a European Neuroendocrine Tumor Society (ENETS) certified center of excellence after this treatment. A total of 41 GEP-NET patients who received PRRT with Lu-177-DOTATATE between 2012 and 2017 at a single center were included in this analysis. Data on pre- and post-PRRT treatments [selective internal radiation therapy (SIRT), somatostatin analogue therapy (SSA), blood parameters, patient symptomatic burden and overall survival] was extracted from patient records. Overall, PRRT was well tolerated and did not increase patient symptomatic burden. Blood parameters were not significantly affected by PRRT (means before and after therapy: hemoglobin: 125.4 vs. 122.3 mg/L, P=0.201; creatinine: 73.8 vs. 77.7 µmol/L, P=0.146), while leukocytes (6.6 vs. 5.6 G/L, P<0.01) and platelets (269.9 vs. 216.7 G/L, P<0.001) were significantly decreased yet without clinical significance in our study. Seven of 9 patients with SIRT treatment prior to PRRT were deceased (mortality odds ratio =4.083). The mortality odds ratio of patients with a pancreatic tumor and SIRT was 1.33 compared to patients with a different tumor origin. 6 of 15 patients (40%) with post-PRRT SSA were deceased (mortality odds ratio =0.429 without SSA after PRRT). Patients with advanced GEP-NET might benefit from PRRT with Lu-177-DOTATATE as it can provide a valuable treatment modality in advanced disease stages. Safety profiles of PRRT were manageable without increasing the symptomatic burden. SIRT before PRRT or lack of SSA after PRRT seem to impair the response and reduce survival.

The predictive impact of dual somatostatin receptor/fluorodeoxyglucose (FDG) positron emission tomography (PET) in metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs): review of literature and a single institution experience.

Treatment with radiolabelled somatostatin analogs, a form of peptide receptor radionuclide therapy (PRRT), has changed the management of patients with advanced gastroenteropancreatic neuroendocrine tumors (GEP-NETs). There is a subgroup of patients who have suboptimal benefit and rapidly progress on PRRT, indicating that accurate prognostic and predictive markers are urgently needed. Currently, most of the literature concentrate on the prognostic impact of the dual positron emission tomography (PET) scan with very few information regarding the predictive value. We report a case series and review the literature to summarizes the predictive value of combined somatostatin receptor (SSTR) and fluorodeoxyglucose (FDG) PET in metastatic GEP-NETs. We conducted a review of the literature for data published from 2010 to 2021 in MEDLINE, Embase, the National Institutes of Health trial registry, Cochrane CENTRAL, and published proceedings from major gastrointestinal and neuroendocrine cancer meetings. Our main criteria included all published prospective and retrospective data in which the predictive value of dual PET scans using SSTR and FDG was correlated with PRRT response in patients with metastatic GEP-NETs. We summarized clinical outcomes including progression-free survival (PFS), overall survival (OS), and post-therapy complications associated with PRRT according to FDG avidity. We excluded studies that did not include FDG PET scan, GEP patients, studies with no clear predictive value of the FDG PET scan, and studies that did not report a direct correlation between FDG avidity and primary outcome. Additionally, we summarized our institutional experience in eight patients who progressed during or within the first year of PRRT treatment. Our search identified 1306 articles; most of them showed only the prognostic value of Integrated SSTR/FDG PET imaging biomarker in GEP-NETs. Only three studies (n=75 patients) met our inclusion criteria and retrospectively investigated the predictive value of dual SSTR and FDG imaging in subjects being considered for PRRT. The results confirmed that FDG avidity correlates with advanced NET grades. Lesions that are both SSTR and FDG avid had early disease progression. In one study, at multivariate analysis, FDG PET results were independently predictive of lower PFS for PRRT. In our case series, there were eight patients with metastatic well-differentiated GEP-NETs (grades 2 and 3) who progressed within one year of PRRT. Seven of them had positive FDG PET scan at the time of progression. In conclusion, Dual SSTR/FDG PET imaging has a potential predictive impact for PRRT in GEP-NETs. It permits the capturing of the disease complexity and aggressiveness, which correlates with PRRT response. Therefore, prospective future trials should validate the predictive value of dual SSTRs/FDG PET for better PRRT stratification.

225Ac-Labeled Somatostatin Analogs in the Management of Neuroendocrine Tumors: From Radiochemistry to Clinic.

The widespread use of peptide receptor radionuclide therapy (PRRT) represents a major therapeutic breakthrough in nuclear medicine, particularly since the introduction of 177Lu-radiolabeled somatostatin analogs. These radiopharmaceuticals have especially improved progression-free survival and quality of life in patients with inoperable metastatic gastroenteropancreatic neuroendocrine tumors expressing somatostatin receptors. In the case of aggressive or resistant disease, the use of somatostatin derivatives radiolabeled with an alpha-emitter could provide a promising alternative. Among the currently available alpha-emitting radioelements, actinium-225 has emerged as the most suitable candidate, especially regarding its physical and radiochemical properties. Nevertheless, preclinical and clinical studies on these radiopharmaceuticals are still few and heterogeneous, despite the growing momentum for their future use on a larger scale. In this context, this report provides a comprehensive and extensive overview of the development of 225Ac-labeled somatostatin analogs; particular emphasis is placed on the challenges associated with the production of 225Ac, its physical and radiochemical properties, as well as the place of 225Ac-DOTATOC and 225Ac-DOTATATE in the management of patients with advanced metastatic neuroendocrine tumors.

Prevalence of Sarcopenia and Impact on Survival in Patients with Metastatic Gastroenteropancreatic Neuroendocrine Tumours.

Sarcopenia in patients with cancer is associated with adverse outcomes such as shorter survival. However, there exists little evidence regarding the prevalence of sarcopenia in patients with metastatic gastroenteropancreatic neuroendocrine tumours (GEP-NETs). Patients with a histologically confirmed newly diagnosed metastatic GEP-NET between 2006 and 2018, CT scan, and anthropometric data at diagnosis were included in this study. CT scans were analysed for the presence of sarcopenia and correlated with overall survival (OS). In total, 183 patients, 87 male (48%), with a median age of 62 years (IQR 52-68 years), were included. In 44 patients (24%), there was a pancreas NET, and in 136 patients, there was a small bowel NET (74%). Sarcopenia was present in 128 patients (69%) and unrelated to BMI (median 25.1). There were significant survival differences between patients with pancreatic and small bowel NETs at 86 vs. 141 months, respectively (p = 0.04). For patients with pancreatic NETs, the presence of sarcopenia was independently associated with shorter OS (HR 3.79 95% CI 1.1-13.03, p-value 0.035). A high prevalence of sarcopenia at the time of diagnosis of a metastatic GEP-NET was seen and associated with worse OS in patients with pancreatic NETs. Further research should focus on how to reverse sarcopenia and its impact on OS and/or quality of life.

Liver resection for gastroenteropancreatic neuroendocrine tumors with extrahepatic disease

Background: Gastroenteropancreatic neuroendocrine tumors (GEP-NET) comprise a heterogenous group of cancers defined by their primary site of origin and malignant potential. The liver is the most common site for metastases, and a significant proportion of these patients also have extrahepatic disease (EHD). We performed a population-based study to characterize the impact of liver resection on survival outcomes for metastatic GEP-NET with concurrent EHD.

Lanreotide Depot to Treat Gastroenteropancreatic Neuroendocrine Tumors in a US Community Oncology Setting: A Prospective, Observational Study.

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) can result in symptoms such as diarrhea, flushing, abdominal pain, and fatigue and are often associated with a significant disease burden and poor prognosis. This non-interventional, prospective, observational study evaluated the real-world safety and effectiveness of lanreotide depot, a somatostatin analog (SSA) used to treat GEP-NETs, in a community setting. In this prospective, non-interventional study (NCT02730104), adult patients with locally advanced (inoperable), metastatic GEP-NETs treated with lanreotide depot were evaluated by their physician every 6 months from enrollment for 24months. Clinically defined time to disease progression (TTDP) and overall survival (OS) were estimated for the total population and by primary tumor type (gastrointestinal [GI], pancreatic, unknown origin), and an exploratory analysis determined the rate of progression-free survival (PFS) at 12 and 24months. Patient satisfaction was evaluated via the Treatment Satisfaction Questionnaire for Medication (TSQM-9), and safety information was recorded. Of 99 patients, the 24-month PFS rate was 73.7% (95% confidence interval [CI] 63.1-81.7) and 24-month OS rate was 84.2% (95% CI 74.0-90.7). Median TTDP was not reached because few patients experienced disease progression during the study period. The majority of responding patients expressed satisfaction with treatment on each domain of the TSQM-9. Treatment-related adverse events (AEs) occurred in 19.2% of patients, while no serious AEs (SAEs) were related to the study drug. Lanreotide depot is an effective and well-tolerated treatment for GEP-NETs in the real-world community setting. ClinicalTrials.gov identifier, NCT02730104.

Liver Cytoreduction Threshold In Metastatic Gastroenteropancreatic Neuroendocrine Tumors (GEP-NETs): Systematic Review of Current Literature

Liver Cytoreduction Threshold In Metastatic Gastroenteropancreatic Neuroendocrine Tumors (GEP-NETs): Systematic Review of Current Literature

Survival Outcomes in Metastatic Gastroenteropancreatic Neuroendocrine Tumor Patients receiving Concomitant 225Ac-DOTATATE Targeted Alpha Therapy and Capecitabine: A Real-world Scenario Management Based Long-term Outcome Study.

Rationale: Although the short-term results of targeted alpha therapy (TAT) with 225Ac-DOTATATE in gastroenteropancreatic neuroendocrine tumors (GEP-NETs) have proven effective, none have assessed the long-term outcome results. In this study, we aimed to evaluate the long-term outcome of 225Ac-DOTATATE targeted alpha therapy (TAT) in patients with somatostatin receptor (SSTR)-expressing advanced-stage metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Methods: Patients with 68Ga-DOTANOC PET/CT scans showing moderate-to-high SSTR expression were recruited. Systemic TAT was performed in 91 adults with GEP-NET [54 males, and 37 females] mean age 54 years (y) (range: 25-75y)] using 225Ac-DOTATATE (100-120 kBq/kg body weight). All patients were given capecitabine therapy as a radiosensitizer (dose 2 g/day) from day 0 to 14 of every 225Ac-DOTATATE treatment cycle. Patients were categorized into three groups based on the status of prior 177Lu-PRRT: prior 177Lu-PRRT-refractory-group; prior 177Lu-PRRT-disease-control group; and 177Lu-PRRT naïve group. Primary endpoints were overall survival (OS), and secondary endpoints included progression-free survival (PFS), objective tumour response, clinical response, and the assessment of treatment-related toxicities. Results: Among the 91 patients, 57 underwent prior 177Lu-DOTATATE therapy [24 disease controlled (PR/SD), 33 progressive diseases (PD)]. A total of 453 225Ac-DOTATATE TAT cycles were administered [median four cycles per patient; range 1-10] in a median follow-up duration of 24 months (range 5-41mo). Median OS was not attained with a 24-month overall survival probability of 70.8%. In multivariate analysis, prognostic factors associated with a poor OS included, the presence bone metastases [HR: 2.501; 95% CI: 1.826 - 5.791; P<0.032], and 225Ac-DOTATATE therapy refractory disease [HR: 8.781; 95% CI: 3.843 - 20.062; P<0.0001]. Median PFS was also not reached with a 24-month progression-free survival probability of 67.5%. The multivariate analysis revealed only 177Lu-PRRT refractory disease significantly associated with a reduced PFS. [HR: 14.338; 95% CI: 1.853 - 97.698; P = 0.011]. Two of 79 patients (2.5%) with assessable disease experienced complete response; 38 (48%) had a partial response, 23 (29%) had SD, and 16 (20.2%) had PD. PD was observed in more patients from the prior 177Lu-PRRT-refractory group (11/33; 34%) as compared to 177Lu-PRRT-naïve patients (4/24; 11%), P-0.056. Patients from the prior 177Lu-PRRT-refractory group had the highest risk of poor PFS [HR:13.91; 95% CI: 4.45 - 42.271; P = 0.0009]. A significant clinical benefit was achieved post 225Ac-DOTATATE therapy with minimal treatment-related toxicities. Conclusion: The long-term results reveal 225Ac-DOTATATE TAT has shown promising results and improves overall survival, even in patients refractory to prior 177Lu-DOTATATE treatment, with transient and acceptable adverse effects.

Advances in the treatment of gastroenteropancreatic neuroendocrine neoplasms with somatostatin analogs

Neuroendocrine neoplasms (NENs) include well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Somatostatin receptors (SSTRs) are highly expressed on NETs cells, and somatostatin analogs (SSAs) could bind to SSTRs with high affinities, regulating cell proliferation and hormone secretion. As many clinical trials have demonstrated the antiproliferative efficacy and safety of SSAs in metastatic gastroenteropancreatic NETs (GEP-NETs), SSAs have been recommended by multiple NEN guidelines as the first-line therapy of GEP-NETs. In recent years, more and more researches have been exploring new therapeutic possibilities of SSA in GEP-NETs, such as high-dose SSA as second-line therapy, SSA in metastatic GEP-NETs with Ki-67 &gt; 10%, SSA as adjuvant therapy for postoperative pancreatic NETs patients, and combinations of SSA with chemotherapy or targeted therapy. In this review, we summarized the latest published or released researches and discussed new application attempts of SSA in GEP-NETs.

Experience with 177Lu-Dotatate in patients with metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NET): Report from a single urban cancer center.

e18688 Background:177Lu-Dotatate is FDA approved for advanced well differentiated (WD) midgut neuroendocrine tumors (NETs). However, questions remain about tolerability and efficacy in patients (pts) with higher grade disease, more than one prior line of treatment, and in non-ileal primaries. Methods: This is a retrospective analysis of pts with histologically proven WD metastatic GEP-NETs who received 177Lu-Dotatate at a single racially diverse urban cancer center. Patients had disease that progressed on systemic therapy that included somatostatin analog (SSA), and radiotracer uptake at disease sites using 68Gallium-Dotate PET/CT. ECOG performance score (PS) was 0 to 2. 177Lu-Dotatate was administered in 200 mCi doses every 8 weeks for a total of 4 cycles and a maximum of 800 mCi. Patients were followed with serial CT scan and/or abdominal MRI with best objective response per RECIST criteria. Results: Fifty-one pts were treated between December 2017 and August 2021. Thirty-eight pts completed a minimum 3-month follow-up imaging. Median age was 64 years, 59% were female, 66% identified as white, 26% as Black, 8% as other. Most frequent primary sites were small intestine (64%) and. All had metastatic disease involving the liver except for one pt. Median time from diagnosis to 177Lu-Dotatate was 51 months (3-201). CTCAE grade 3/4 hematologic toxicity was seen in 6 of 51 pts (12%). Grade 3/4 thrombocytopenia occurred in 3 pts, grade 3/4 leukopenia occurred in 2 pts and grade 3 anemia occurred in 1 pt. A single pt developed myelodysplastic syndrome 1 year after 177Lu-Dotatate. Non-white pts had significantly higher risk of grade 1 elevated creatinine at 38% vs 6% in those who identified as white (p = 0.015). Of the 37 pts who reached 3-month follow-up, 27% had partial response, 43% had a mixed/stable response, and 30% had progressive disease. Only gender demonstrated significant difference; with male gender associated with worse response categories (p = 0.001). Median OS was 3.09 years. Metastatic disease in the liver only was associated with significantly worse OS (p = 0.015) compared to liver and other tissues. The median PFS was 1.36 years. Metastatic disease in the liver only was associated with significantly worse PFS (p = 0.043). Higher tumor grade neared significant association with worse PFS (p = 0.053). There was no difference in PFS by race, primary tumor site (pancreatic vs small bowel), PS, prior treatment history or time to first 177Lu-Dotatate. Conclusions: Diverse patients with WD GEP-NETs treated at this single urban cancer center with 177Lu-Dotatate demonstrated acceptable toxicity. Median PFS and OS were inferior to reported outcomes in NETTER-1 probably because of differences in treatment timing and patient populations. Possible variables associated with difference in outcome include pattern of metastatic disease and tumor grade.

The Interplay of Four Main Pathways Recomposes Immune Landscape in Primary and Metastatic Gastroenteropancreatic Neuroendocrine Tumors.

BackgroundThe four major pathways in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) including chromatin remodeling, DNA damage repair, activation of mTOR signaling, and telomere maintenance were mediated by some critical molecules and constituted critical processes of regulation in cancer-causing processes. However, the interplay and potential role of these pathway-related molecules in the tumor microenvironment of the primary and metastatic site remained unknown.MethodsWe systematically evaluated the mRNA expression of 34 molecules associated with the four pathways in 227 GEP−NEN samples from 5 datasets. We assigned the samples into two expression patterns of pathway-related molecules by an unsupervised clustering method. Subsequently, we explored the specific cell-related molecules, especially immune and stromal cells using the WGCNA method, based on differentially expressed genes (DEGs) responsible for the different patterns of pathway-related molecules, which provided a new method to qualify the pathway-related subtypes of individual tumors, then the PC_Score and PI_Score scoring systems were also constructed using obtained specific cell-related molecules. Furthermore, we performed the association of pathway-related subtypes with characteristics of immune landscape in primary and metastatic GEP-NENs.ResultsWe demonstrated that the specific pathway-related molecules (SMARCA4, MLH1, TSC1, ATRX, and ATR) were associated with cytolytic activity. Then we identified the two distinct patterns of pathway-related molecules, which were characteristic with a significantly distinct immune landscape. Using WGCNA, we also identified the fibroblast-related molecules, including ASPN, COL10A1, COL3A1, EDNRA, MYL9, PRELP, RAB31, SPARC, and THBS2, and immune-related molecules including CASP1, CCL5, CTSS, CYBRD1, PMP22, and TFEC. Based on these specific markers, we identified four distinct pathway-related subtypes, characterized by immune and fibrotic enriched (I/FE), immune enriched (IE), fibrotic enriched (FE), and immune and fibrotic desert (I/FD), of which I/FE was characteristic with the highest PC_Score and PI_Score whereas I/FD presents the opposite trend. I/FE was positively correlated with immune landscape of T-cell activation and immunosuppression. Furthermore, the I/FE marked GEP-NENs with increased immune activation scores (T-cell costimulation, MHC I presentation, and APC costimulation). Importantly, the four distinct pathway-related subtypes were not conserved in different tumor sites, because I/FE was lacking in the liver metastatic site even though IE, FE, and I/FD also could be observed in the metastatic site.ConclusionsThis study was the first to perform a comprehensive analysis of the four major pathways in GEP-NENs. We demonstrated the potential function of these pathway-related molecules in immune landscapes. Our findings indicated that the primary and metastatic GEP-NENs had distinct antitumor phenotypes. This work highlighted the interplay and potential clinical utility of these pathway-related molecules in GEP-NENs.