Real-World Treatment Patterns and Clinical Outcomes in Advanced Gastrointestinal Neuroendocrine Tumors (GI NET): A Multicenter Retrospective Chart Review Study

What have we learnt from the past - would treatment decisions for GEP-NET patients differ between 2012 to 2016 by the new recommendations in 2022?

BACKGROUND

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a heterogeneous group of tumors with a broad range of local and systemic treatment options. Still a lack of data regarding treatment sequences exists. The aim of this study was to analyse outcomes in GEP-NETs depending on stage and treatment steps and compare our treatment decisions to the latest treatment recommendations of European Society of Medical Oncology (ESMO) 2020 for GEP-NETs.

METHODS

Patients were included in this retrospective single-center analysis from 2012-2016. All patients suffering from a GEP-NET, who were screened, treated or evaluated at ENETS Center in Zurich, Switzerland were included in analysis. Patients with any other diagnosis of NET were not included. We used Kaplan Meier estimator as well as Cox regression to compare survival rates between different sites of localization, grades or stages and treatment sequences.

RESULTS

Overall, we identified 256 GEP-NETs, most in advanced stage (62%) and located in small intestine tract or pancreatic gland. Survival depended on stage, grade, primary site and duration of response for the early systemic treatment. On average patients underwent 2.6 different treatment modalities, mostly depending on stage and higher tumor grade. Surgery was performed early but also in advanced stages, usually followed by Somatostatine-Agonist modalities. In distant disease (Stage IV), we investigated a positive effect of PFS after treatment with Somatostatine Analogues (SSA) (hazard ratio [HR], 0.45; 95% confidence interval [CI], 0.21 - 0.97; p = 0.04) and systemic treatment (HR, 0.51; 95% CI, 0.26 - 0.99; p = 0.047) if patients underwent prior surgery or endoscopic resection. Kaplan Meier distributions predict shorter OS in distant disease (Stage IV), (Figure. 1; HR, 2.06; 95% CI, 1.46 - 2.89; log-rank test, p < 0.001).

CONCLUSION

This retrospective analysis presents a great overview of all patients', disease and treatment characteristics of GEP-NETs at ENETS Center in Zurich, Switzerland. We illustrated survival (PFS) depending on implemented therapies. According to these findings, we formed a suggested treatment algorithm for advanced GEP-NETs, which does not differ from the latest treatment recommendation by ESMO guidelines for GEP-NETs. The results of this project may define GEP-NET patients' selection for upcoming clinical prospective studies.

Epidemiological trends and novel prognostic evaluation approaches of patients with stage II-IV colorectal neuroendocrine neoplasms: A population-based study with external validation

OBJECTIVE

This study aimed to clarify the incidence trend of all-stage colorectal neuroendocrine neoplasms (CRNENs), overall survival (OS), and disease-specific survival (DSS) of patients with stage II-IV CRNENs, and to establish relevant nomograms for risk stratification.

METHODS

Among all patients diagnosed with CRNENs in the Surveillance, Epidemiology, and End Results (SEER) database from 1975 to 2019, temporal trends in incidence were assessed. Clinical data of 668 patients with stage II-IV CRNENs from 2010 to 2016 were extracted for survival analysis. Patients were randomly divided into a training cohort and a validation cohort at a ratio of 7:3. Univariate and multivariate cox regression analyses were utilized to identify independent prognostic factors affecting OS outcomes. Competing risk analysis was applied to investigate risk factors related to the DSS of CRNENs. Two nomograms specifically for OS and DSS were developed for patients with stage II-IV CRNENs, their prognostic capabilities were evaluated using calibration curves, receiver operating characteristic (ROC) curves, the time-dependent area under the curve (AUC), and decision-curve analysis (DCA). Our hospital's independent cohort of 62 patients with CRNENs was used as the external validation cohort.

RESULTS

In the period of 1975-2019, the incidence of CRNENs increased steadily with an annual percentage change (APC) of 4.50 (95% confidence interval [CI]: 3.90-5.11, P < 0.05). In total, 668 patients with stage II-IV CRNENs were included in the survival analysis from 2010 and 2016. Independent adverse prognostic factors for both OS and DSS of CRNENs prior treatment included grade III/IV (HR for OS: 4.66, 95%CI: 2.92-7.42; HR for DSS: 4.79, 95%CI: 4.27-5.31), higher TNM stage ([stage III vs stage II] HR for OS: 2.22, 95%CI: 1.25-3.94; HR for DSS: 2.69, 95%CI: 1.96-3.42. [stage IV vs stage II] HR for OS: 3.99, 95%CI: 2.03-7.83; HR for DSS: 4.96, 95%CI: 4.14-5.78), liver metastasis (HR for OS: 1.61, 95%CI: 1.03-2.51; HR for DSS: 1.86, 95%CI: 1.39-2.32), and brain metastasis (HR for OS: 4.57, 95%CI: 1.66-12.58; HR for DSS: 5.01, 95%CI: 4.15-5.87). Advanced age was also identified as a risk factor for OS (HR: 2.03, 95%CI: 1.5-2.76) but not DSS. In terms of treatment, surgery can significantly prolong OS (HR: 0.62, 95%CI: 0.44-0.86) and DSS (HR: 0.67, 95%CI: 0.29-1.05), but chemotherapy and radiation failed to show significance. The respective nomograms for OS and DSS for stage II-IV CRNENs demonstrated high accuracy and robust prediction value in predicting 1-year, 3-year, and 5-year OS and DSS outcomes in training, internal validation, and external validation cohorts. Besides, two online tools regarding OS and DSS prediction were established, facilitating nomogram score calculation, risk group determination, as well as survival prediction for each individual patient.

CONCLUSION

Over the past 40 years, the incidence of CRNENs presented increased steadily, along with improved survival outcomes. Grade III-IV, higher TNM stage, liver metastasis, brain metastasis, and without receiving surgery were found to be associated with worse OS and DSS. Advanced age was a risk factor for OS but not DSS. Nomograms for patients with stage II-IV stage CRNENs are capable of predicting the 1-, 3-, and 5-year OS and DSS rates with high accuracy, and realize risk stratification.

A practical proposal on treatment sequencing of metastatic well-differentiated neuroendocrine tumours

According to the neuroendocrine tumour (NET) characteristics, 3 to 7 different treatment options are available, corresponding to 6 to 5,040 theoretical different sequences. Even though each patient is unique and despite a large heterogeneity in NET characteristics, the present review aims to discuss the main sequences and addresses how one can propose the best sequence to treat metastatic NET (mNET) on a case-by-case basis. Each treatment must be discussed during dedicated multi-disciplinary meetings, and inclusions in clinical trials should be favoured. After a thorough characterization of patients and their mNET, and taking into account the availability of drugs, the first-line treatment should be chosen according to the treatment aim. The latter is determined based on three main topics (efficacy, safety, and patient preferences) that do not necessarily converge and must be defined a priori. At baseline, physicians should design an a priori full therapeutic sequence, which may evolve at each step depending on the response to previous treatment, the occurrence of chronic toxicities, and the patients' perception of the prior treatment. To improve knowledge in terms of effectiveness and risk of cumulative toxicities regarding the different sequences, real-world data using long follow-up durations are necessary; such issues will not be resolved by randomized clinical trials.

Treatment Patterns and Survival among Patients with Metastatic Gastroenteropancreatic Neuroendocrine Tumours in Sweden - a Population-based Register-linkage and Medical Chart Review Study

Background: Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) are neoplasms derived from the endocrine system in the gastrointestinal tract and pancreas. Treatment options include surgery; pharmacological treatments like somatostatin analogues (SSA), interferon alpha, molecular targeted therapy and chemotherapy; and peptide receptor radionuclide therapy.

The objective of this study was to describe treatment patterns and survival among patients with metastatic GEP-NET grade 1 or 2 in Sweden.

Methods: Data was obtained via linkage of nationwide registers. Patients diagnosed with metastatic GEP-NET grade 1 or 2 in Sweden between 2005 and 2013 were included (n=811; National population). In addition, medical chart review was performed for the subpopulation diagnosed at Sahlgrenska University Hospital, Gothenburg (n=127; Regional population). Treatment patterns, including treatment sequences, and overall survival were assessed.

Results: Most patients had small intestinal NET (76%). In the regional population, 72% had grade 1 tumours; 50% had functioning tumours. The two most common first-line treatments were surgery (57%) and SSA (25%). After first-line surgery, 46% received SSA, while 40% had no further treatment. After first-line SSA, 52% received surgery, while 27% had no further treatment. Overall median survival time from date of diagnosis was 7.0 years (95% CI 6.2-not reached). Among patients with distant metastases, pancreatic NET (vs. small intestinal NET) was associated with poorer survival (HR 1.9; 95% CI 1.1-3.3), as were liver metastases (HR 3.2; 95% CI 1.5-7.0).

Conclusions: First-line surgery was typically followed by SSA or no further treatment. Among patients with distant metastases, pancreatic NET or liver metastases were associated with a poorer survival.