Prospective Evaluation of MGMT-Promoter Methylation Status and Correlations with Outcomes to Temozolomide-Based Chemotherapy in Well-Differentiated Neuroendocrine Tumors

Peptide Receptor Radionuclide Therapy versus Capecitabine/Temozolomide for the Treatment of Metastatic Pancreatic Neuroendocrine Tumors

Background: Peptide Receptor Radionuclide Therapy (PRRT), a form of Radioligand Therapy (RLT), and Capecitabine/Temozolomide (CAPTEM) are cornerstones of systemic therapy for metastatic pancreatic neuroendocrine tumors (PNETs). Data regarding comparative efficacy are lacking. Herein, we compare the efficacy of PRRT vs. CAPTEM as second-line/beyond regimens and treatment sequencing. Methods: Clinicopathologic, radiographic, and genomic data were captured for metastatic PNETs seen in our multi-disciplinary NET clinic between 2013 and 2023. The primary outcome was progression-free survival (PFS) after progression on a previous line of systemic therapy. The secondary outcomes were objective response rate (ORR), time to response (TTR), and overall survival (OS). Results: Fifty-nine cases were included. PFS was similar in the PRRT (n = 29) and CAPTEM (n = 30) groups (PRRT = 21.90 months vs. CAPTEM = 20.03 months; HR 0.99; p = 0.97). On subgroup analysis, PRRT had longer PFS in cases without extrahepatic metastases (26.47 months vs. 17.67 months; p = 0.03) and cases with a mutation in the MEN1, DAXX, and/or ATRX genes (28.43 months vs. 18.67 months; p = 0.03). PRRT had reduced PFS in patients with grade 3 disease (7.83 months vs. 16.33 months; p = 0.02). ORR did not vary significantly (34.78% vs. 40.91%; p = 0.67). CAPTEM responders showed shorter TTR (6.03 months vs. 11.15 months; p = 0.03). In patients who received both, OS did not vary based on the sequence (HR 1.20; p = 0.75). Conclusions: PFS, ORR, and OS are similar when using PRRT vs. CAPTEM as second-line-and-beyond therapy for patients with metastatic PNETs. However, patients with MEN1, DAXX, and/or ATRX mutations or without extrahepatic metastases might better benefit from PRRT and patients with grade 3 disease from CAPTEM. Candidates for surgical debulking or with tumor-induced symptoms may benefit from initial treatment with CAPTEM due to shorter TTR.

Temozolomide (TMZ) in the Treatment of Glioblastoma Multiforme-A Literature Review and Clinical Outcomes

Glioblastoma multiforme (GBM) is one of the most aggressive primary tumors of the central nervous system. It is associated with a very poor prognosis, with up to half of patients failing to survive the first year after diagnosis. It develops from glial tissue and belongs to the adult-type diffuse glioma group according to the WHO classification of 2021. Therapy for patients with GBM is currently based on surgical resection, radiation therapy, and chemotherapy, but despite many efforts, there has been minimal progress in tumor management. The most important chemotherapeutic agent in the treatment of this tumor is temozolomide (TMZ), a dacarbazine derivative that presents alkylating activity. It is usually administered to patients concurrently with radiation therapy after surgical resection of the tumor, which is defined as the Stupp protocol. Temozolomide demonstrates relatively good efficacy in therapy, but it could also present with several side effects. The resistance of GBM to the drug is currently the subject of work by specialists in the field of oncology, and its use in various regimens and patient groups may bring therapeutic benefits in the future. The aim of this review paper is to summarize the relevance of TMZ in the treatment of GBM based on recent reports.

Treatment, Prognostic Markers, and Survival in Thymic Neuroendocrine Tumors, with Special Reference to Temozolomide-Based Chemotherapy

BACKGROUND

Thymic neuroendocrine tumors (Th-NETs) are rare and aggressive, with a scarcity of research on predicting patient prognosis. Our study aimed to assess the impact of prognostic markers and temozolomide (TMZ)-based chemotherapy on survival in Th-NETs.

METHODS

We retrospectively reviewed the medical records of patients diagnosed with Th-NETs between 2013 and 2023 at our institution. We collected clinicopathological data, including tumor pathological grading, staging, serum concentrations of neuron-specific enolase (NSE) and pro-gastrin-releasing peptide, levels of inflammatory factors, and expression of oxygen 6-methylguanine-DNA methyltransferase (MGMT). Treatment details (such as surgery and chemotherapy) and survival outcomes were also documented.

RESULTS

A total of 32 patients were included in our study after excluding those without complete available information. The median progression-free survival (PFS) was 12.5 months (95%CI, 8-16 months) for 19 patients who received TMZ-based chemotherapy. Twenty-one patients underwent surgery as the primary treatment, demonstrating a median disease-free survival (DFS) of 51.0 months. The inflammatory factor neutrophil-to-lymphocyte ratio (NLR) was an independent prognostic indicator of DFS in postoperative patients and PFS in TMZ-treated patients. The overall 3-, 5-, and 10-year survival rates were 86.6%, 69.5%, and 33.8%, respectively. Ki67 level exceeding 10% (p = 0.048) and absence of surgical resection (p = 0.003) were significantly associated with worse overall survival (OS).

CONCLUSION

Surgical treatment was currently the primary method for treating Th-NETs, and postoperative adjuvant therapy was an essential consideration for specific patient cohorts. Despite widespread positive MGMT expression, TMZ-based chemotherapy showed promise. Some potential prognostic biomarkers such as NLR and NSE need more attention.

Pancreatic Neuroendocrine Tumors: Signaling Pathways and Epigenetic Regulation

Pancreatic neuroendocrine tumors (PNETs) are characterized by dysregulated signaling pathways that are crucial for tumor formation and progression. The efficacy of traditional therapies is limited, particularly in the treatment of PNETs at an advanced stage. Epigenetic alterations profoundly impact the activity of signaling pathways in cancer development, offering potential opportunities for drug development. There is currently a lack of extensive research on epigenetic regulation in PNETs. To fill this gap, we first summarize major signaling events that are involved in PNET development. Then, we discuss the epigenetic regulation of these signaling pathways in the context of both PNETs and commonly occurring-and therefore more extensively studied-malignancies. Finally, we will offer a perspective on the future research direction of the PNET epigenome and its potential applications in patient care.

Updates in histopathological classification and tissue biomarkers of digestive neuroendocrine neoplasms: What the clinician should know

Histopathological classifications of neuroendocrine neoplasms (NEN) change regularly and the latest WHO classification published in 2022, which concerns all NEN in the body, attempts to standardize classifications in the different locations. Differentiation and proliferation mainly assessed by Ki-67 index are still the cornerstone of those classifications. However, many markers are now used for diagnostic (to check neuroendocrine differentiation, to identify the site of origin of a metastasis, to help separating high-grade neuroendocrine tumors/NET and neuroendocrine carcinoma/NEC), prognostic or theranostic purposes. NENs are often heterogeneous and this can lead to difficulties in classifications, biomarker and prognostic assessment. These different points are discussed successively in this review, insisting especially on the frequent digestive, gastro-entero-pancreatic (GEP) localizations.