Usefulness of an immunohistochemical score in advanced pancreatic neuroendocrine tumors treated with CAPTEM or everolimus

Predictive Factors for Resistant Disease with Medical/Radiologic/Liver-Directed Anti-Tumor Treatments in Patients with Advanced Pancreatic Neuroendocrine Neoplasms: Recent Advances and Controversies

Simple Summary

Tumor resistance, both primary and acquired, is leading to increased complexity in the nonsurgical treatment of patients with advanced panNENs, which would be greatly helped by reliable prognostic/predictive factors. The importance in identifying resistance is being contributed to by the increased array of possible treatments available for treating resistant advanced disease; the variable clinical course as well as response to any given treatment approach of patients within one staging or grading system, the advances in imaging which are providing increasing promising results/parameters that correlate with grading/outcome/resistance, the increased understanding of the molecular pathogenesis providing promising prognostic markers, all of which can contribute to selecting the best treatment to overcome resistance disease. Several factors have been identified that have prognostic/predictive value for identifying development resistant disease and affecting overall survival (OS)/PFS with various nonsurgical treatments of patients with advanced panNENs. Prognostic factors identified for patients with advanced panNENs for both OS/PFSs include various clinically-related factors (clinical, laboratory/biological markers, imaging, treatment-related factors), pathological factors (histological, classification, grading) and molecular factors. Particularly important prognostic factors for the different treatment modalities studies are the recent grading systems. Most prognostic factors for each treatment modality for OS/PFS are not specific for a given treatment option. These advances have generated several controversies and new unanswered questions, particularly those related to their possible role in predicting the possible sequence of different anti-tumor treatments in patients with different presentations. Each of these areas is reviewed in this paper.

Abstract

Purpose: Recent advances in the diagnosis, management and nonsurgical treatment of patients with advanced pancreatic neuroendocrine neoplasms (panNENs) have led to an emerging need for sensitive and useful prognostic factors for predicting responses/survival. Areas covered: The predictive value of a number of reported prognostic factors including clinically-related factors (clinical/laboratory/imaging/treatment-related factors), pathological factors (histological/classification/grading), and molecular factors, on therapeutic outcomes of anti-tumor medical therapies with molecular targeting agents (everolimus/sunitinib/somatostatin analogues), chemotherapy, radiological therapy with peptide receptor radionuclide therapy, or liver-directed therapies (embolization/chemoembolization/radio-embolization (SIRTs)) are reviewed. Recent findings in each of these areas, as well as remaining controversies and uncertainties, are discussed in detail, particularly from the viewpoint of treatment sequencing. Conclusions: The recent increase in the number of available therapeutic agents for the nonsurgical treatment of patients with advanced panNENs have raised the importance of prognostic factors predictive for therapeutic outcomes of each treatment option. The establishment of sensitive and useful prognostic markers will have a significant impact on optimal treatment selection, as well as in tailoring the therapeutic sequence, and for maximizing the survival benefit of each individual patient. In the paper, the progress in this area, as well as the controversies/uncertainties, are reviewed.

Should temozolomide be used on the basis of O6-methylguanine DNA methyltransferase status in patients with advanced neuroendocrine tumors? A systematic review and meta-analysis

BACKGROUND

Temozolomide (TEM) is an active treatment in metastatic neuroendocrine tumors (NETs). Patients affected by glioblastoma multiforme or advanced melanoma treated with TEM who have deficiency of O⁶-methylguanine DNA methyltransferase (MGMT) have a better responses and survival. However, the predictive role of MGMT in patients with NETs treated with TEM is still debated.

METHODS

We conducted a systematic review of the literature and meta-analysis, based on PRISMA methodology, searching in the main databases (PubMed, Embase, Scopus, Web of Science, Cochrane Library and clinical trial.gov) and the proceedings of the main international congresses, until April 26, 2021.

RESULTS

Twelve out of 616 articles were selected for our analysis, regarding a total of 858 NET patients treated with TEM-based chemotherapy. The status of MGMT had been tested in 513 (60%) patients, using various methods. The pooled overall response rate (ORR) was higher in MGMT-deficient compared with MGMT-proficient NETs, with a risk difference of 0.31 (95% confidence interval, CI: 0.13-0.50; p < 0.001; I²: 73%) and risk ratio of 2.29 (95% CI: 1.34-3.91; p < 0.001; I²: 55%). The pooled progression free survival (PFS) (hazard ratio, HR = 0.56; 95% CI: 0.43-0.74; p < 0.001) and overall survival (OS) (HR = 0.41; 95% CI: 0.20-0.62; p = 0.011) were longer in MGMT-deficient versus MGMT-proficient NETs.

CONCLUSIONS

Our meta-analysis suggested that MGMT status may be predictive of TEM efficacy. However, due to the high heterogeneity of the evaluated studies the risk of biases should be considered. On this hypothesis future homogeneous prospective studies are warranted.