Neoadjuvant PRRT for advanced pNEN: an unusual highlander

Role of neoadjuvant peptide receptor radionuclide therapy in unresectable and metastatic gastro-entero-pancreatic neuroendocrine neoplasms: A scoping review

Peptide receptor radionuclide therapy (PRRT) is an established therapy for metastatic neuroendocrine neoplasms (NEN). The role of PRRT as a neoadjuvant treatment prior to surgery or other local therapies is uncertain. This scoping review aimed to define the landscape of evidence available detailing the utility of PRRT in the neo-adjuvant setting, including the clinical contexts, efficacy, and levels of evidence. A comprehensive literature search of PUBMED, SCOPUS, and EMBASE through to December 2022 was performed to identify reports of PRRT use as neoadjuvant therapy prior to local therapies. Observational studies and clinical trials were included. A total of 369 records were identified by the initial search, and 17 were included in the final analysis, comprising 179 patients treated with neoadjuvant PRRT. Publications included case reports, retrospective cohort series and a phase 2 trial. Definitions of unresectable disease were variable. Radioisotopes used included 177Lu (n = 142) and 90Y (n = 36), used separately (n = 178) or in combination (n = 1). A combination of PRRT with chemotherapy was also explored (n = 2). Toxicity data was reported in 11/17 studies. Survival analysis was reported in 3/17 studies. Surgical resection following PRRT was reported for both the primary tumor (n = 71) and metastases (n = 12). Resection rates could not be calculated as not all publications reported whether resection was completed. Published literature exploring the use of PRRT in the neoadjuvant setting is mostly limited to case reports and retrospective cohort studies. From these limited data there is reported to be a role of PRRT in neoadjuvant setting in the literature. However, the low quality of evidence precludes any definite conclusion on the grade of disease, site of primary, isotope used or use of concomitant chemotherapy that can benefit from this application. Further prospective studies will require collaboration between multiple centers to gain sufficient high-quality evidence.

Prognostic factors after resection of locally advanced non-functional pancreatic neuroendocrine neoplasm: an analysis from the German Cancer Registry Group of the Society of German Tumor Centers

OBJECTIVE

The available literature regarding outcome after pancreatic resection in locally advanced non-functional pNEN (LA-pNEN) is sparse. Therefore, this study evaluates the current survival outcomes and prognostic factors in after resection of LA-pNEN.

MATERIALS AND METHODS

This population-based analysis was derived from 17 German cancer registries from 2000 to 2019. Patients with upfront resected non-functional non-metastatic LA-pNEN were included.

RESULTS

Out of 2776 patients with pNEN, 277 met the inclusion criteria. 137 (45%) of the patients were female. The median age was 63 ± 18 years. Lymph node metastasis was present in 45%. G1, G2 and G3 pNEN were found in 39%, 47% and 14% of the patients, respectively. Resection of LA-pNEN resulted in favorable 3-, 5- and 10-year overall survival of 79%, 74%, and 47%. Positive resection margin was the only potentially modifiable independent prognostic factor for overall survival (HR 1.93, 95% CI 1.71-3.69, p value = 0.046), whereas tumor grade G3 (HR 5.26, 95% CI 2.09-13.25, p value < 0.001) and lymphangiosis (HR 2.35, 95% CI 1.20-4.59, p value = 0.012) were the only independent prognostic factors for disease-free survival.

CONCLUSION

Resection of LA-pNEN is feasible and associated with favorable overall survival. G1 LA-pNEN with negative resection margins and absence of lymph node metastasis and lymphangiosis might be considered as cured, while those not fulfilling these criteria might be considered as a high-risk group for disease progression. Herein, negative resection margins represent the only potentially modifiable prognostic factor in LA-pNEN but seem to be influenced by tumor grade.

Radioligand therapy (RLT) as neoadjuvant treatment for inoperable pancreatic neuroendocrine tumors: a literature review

In the last 10 years, several literature reports supported radioligand therapy (RLT) in neoadjuvant settings for pancreatic neuroendocrine tumors (PanNETs). Indeed, primary tumor shrinkage has been frequently reported following RLT in unresectable or borderline resectable PanNETs. Moreover, RLT-induced intratumoral modifications facilitate surgery, both on primary tumor and metastasis, having a great impact on progression free survival (PFS), overall survival (OS) and quality of life (QoL). However, prospective controlled investigations are necessary to confirm preliminary data and to define the best RLT scheme and the ideal patient that, in a multidisciplinary approach, should be referred to neoadjuvant RLT.