Single centre retrospective review of outcome of 177 Lu-DOTATATE peptide receptor radionuclide therapy in the treatment of progressive metastatic neuroendocrine tumours: Survival, toxicity, and prognostic factors

Somatostatin receptor-linked α-particle therapy in neuroendocrine tumours

The incidence and prevalence of neuroendocrine tumours (NETs) are on the rise, but to date, only complete surgical resection is curative. Among the various therapeutic options for metastatic disease, peptide receptor radionuclide therapy (PRRT), linking a radioactive moiety to an octreotide derivative, has been shown to be highly efficacious and a well-tolerated therapy, improving progression-free survival and prolonging overall survival. Nevertheless, complete responses are rare, and the current β-particle emitters have non-optimal radiobiological properties. A new generation of α-particle-emitting radionuclides is being developed, with the advantages of very high energy and a short path length. We survey the most recent developments in this field, summarising the result of currently performed studies in this potentially ground-breaking novel form of therapy for NETs.

Extended peptide receptor radionuclide therapy: evaluating nephrotoxicity and therapeutic effectiveness in neuroendocrine tumor patients receiving more than four treatment cycles

PURPOSE

Currently, the most used peptide receptor radionuclide therapy (PRRT) regimen for neuroendocrine tumors comprises 4 treatment cycles, and there is not enough large-scale data to support the safety of more individualized extended PRRT. This study aims to evaluate the therapeutic effectiveness and potential nephrotoxicity related to PRRT using more than four treatment cycles.

METHODS

In this retrospective analysis, we included patients who had received at least four PRRT cycles and had available follow-up data. We analyzed renal function indicators before and after multiple treatments, comparing nephrotoxicity in patients receiving four cycles ("standard") with those receiving more than four ("extended treatment"). Nephrotoxicity was assessed via creatinine levels and CTCAE creatinine grades. Treatment effectiveness was gauged using Kaplan-Meier survival analysis, focusing on overall survival and disease-specific survival (DSS). Statistical analyses were performed using SPSS version 26 (IBM), R 4.2.3, and GraphPad Prism 9.0.0. Statistical significance was defined as a P-value of less than 0.05.

RESULTS

Our study cohort consisted of 281 patients in the standard group and 356 in the extended treatment group. No significant differences in baseline characteristics or renal function were noted between the two groups pre-treatment. Mean post-treatment creatinine levels did not significantly differ between the standard (89.30 ± 51.19 μmol/L) and extended treatment groups (93.20 ± 55.98 μmol/L; P = 0.364). Similarly, there was no statistical significance between the CTCAE creatinine grades of the two groups (P = 0.448). Adverse renal events were observed in 0.4% of patients in the standard group and 1.1% in the extended treatment group. After a median follow-up time of 88.3 months, we found that median overall survival was significantly higher in the extended treatment group (72.8 months) compared to the standard treatment group (52.8 months). A Cox regression analysis further supported these findings, indicating a better prognosis for the extended treatment group in terms of overall survival (HR: 0.580, P < 0.001) and DSS (HR: 0.599, P < 0.001).

CONCLUSION

Our findings suggest that extending PRRT treatment beyond the standard four cycles may be a safe and effective therapeutic strategy for NET patients. This approach could be particularly beneficial for patients experiencing disease recurrence or progression following standard treatment.

Non-cirrhotic hyperammonaemic encephalopathy secondary to metastatic pancreatic neuroendocrine tumour treated with peptide receptor radio nucleotide therapy and transarterial chemoembolisation

Neuroendocrine tumours (NETs) are rare cancers which often carry significant morbidity and mortality, frequently related to burden of liver metastases. Hyperammonaemia and subsequent hepatic encephalopathy carries a poor prognosis and has been described in these patients. We discuss a case of a woman in her 50s with hyperammonaemic encephalopathy and a new diagnosis of pancreatic NET with hepatic metastases. She presented with a reduced conscious state a few days post commencing chemotherapy. This was considered to have a multifactorial pathophysiology: the primary driver being large volume hepatic metastases and contributed by portosystemic microshunting, sepsis, severe weight loss and malnutrition. We describe how each of these exacerbating factors was addressed and highlight the effective multimodal treatment approach consisting of sequential transarterial chemoembolisation followed by peptide receptor radio nucleotide therapy, resulting in the resolution of hyperammonaemic encephalopathy and radiological partial metabolic response.

Safety and efficacy of peptide receptor radionuclide therapy in patients with advanced pheochromocytoma and paraganglioma: A single-institution experience and review of the literature

INTRODUCTION

Despite advances in diagnosis and management, patients with advanced pheochromocytomas and paragangliomas (PPGL) face limited treatment options. This study aims to evaluate the safety and efficacy of peptide receptor radionuclide therapy (PRRT) in patients with advanced PPGL, based on a single-institution experience and provide a comprehensive review of the literature.

METHODS

A retrospective analysis was conducted on patients with advanced pheochromocytoma and paraganglioma who received PRRT at a single institution from April 2012 to March 2022. Clinical characteristics, treatment response, adverse events, and survival outcomes were assessed. A systematic literature review was also performed.

RESULTS

A total of 15 patients with advanced PPGL were included, the majority of whom had both metastatic and functional disease. Most patients received four infusions of 177Lu-DOTATATE (73%). The median therapeutic 177Lu-DOTATATE radioactivity for each infusion was 7.4 GBq. Only one patient was treated with one infusion of 90Y-DOTATATE (4.2 GBq) in addition to three infusions of Lu-177 DOTATATE. Overall, PRRT suggests a promising efficacy with disease control rate of 63.6% by RECIST v1.1. The median overall survival (OS) was not reached and the median progression free survival (PFS) was 25.9 months. In terms of safety, PRRT was well tolerated. Review of the literature revealed consistent findings, supporting the efficacy and safety of PRRT in PPGL.

CONCLUSION

This study suggests that PRRT is a safe and effective therapeutic option for patients with PPGL. Our findings align with the existing literature, providing additional evidence to support the use of PRRT in this challenging patient population.

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.