Radioimmunotherapy (RIT) in Brain Tumors

Advances in Neuro-Oncological Imaging: An Update on Diagnostic Approach to Brain Tumors

This study delineates the pivotal role of imaging within the field of neurology, emphasizing its significance in the diagnosis, prognostication, and evaluation of treatment responses for central nervous system (CNS) tumors. A comprehensive understanding of both the capabilities and limitations inherent in emerging imaging technologies is imperative for delivering a heightened level of personalized care to individuals with neuro-oncological conditions. Ongoing research in neuro-oncological imaging endeavors to rectify some limitations of radiological modalities, aiming to augment accuracy and efficacy in the management of brain tumors. This review is dedicated to the comparison and critical examination of the latest advancements in diverse imaging modalities employed in neuro-oncology. The objective is to investigate their respective impacts on diagnosis, cancer staging, prognosis, and post-treatment monitoring. By providing a comprehensive analysis of these modalities, this review aims to contribute to the collective knowledge in the field, fostering an informed approach to neuro-oncological care. In conclusion, the outlook for neuro-oncological imaging appears promising, and sustained exploration in this domain is anticipated to yield further breakthroughs, ultimately enhancing outcomes for individuals grappling with CNS tumors.

Quantifying intraventricular drug delivery utilizing programmable ventriculoperitoneal shunts as the intraventricular access device

PURPOSE

Programmable ventriculoperitoneal shunts (pVP shunts) are increasingly utilized for intraventricular chemotherapy, radioimmunotherapy, and/or cellular therapy. Shunt adjustments allow optimization of drug concentrations in the thecal space with minimization in the peritoneum. This report assesses the success of the pVP shunt as an access device for intraventricular therapies. Quantifying intrathecal drug delivery using scintigraphy by pVP shunt model has not been previously reported.

METHODS

We performed a single-institution, retrospective analysis on patients with CNS tumors and pVP shunts from 2003 to 2020, noting shunt model. pVP flow was evaluated for consideration of compartmental radioimmunotherapy (cRIT) using In-111-DTPA scintigraphy. Scintigraphy studies at 2-4 h and at 24 h quantified ventricular-thecal and peritoneal drug activity.

RESULTS

Twenty-two CSF flow studies were administered to 15 patients (N = 15) with diagnoses including medulloblastoma, metastatic neuroblastoma, pineoblastoma, and choroid plexus carcinoma. Six different types of pVP models were noted. 100% of the studies demonstrated ventriculo-thecal drug activity. 27% (6 of 22) of the studies had no peritoneal uptake visible by imaging. 73% (16 of 22) of the studies had minimal relative peritoneal uptake (< 12%). 27% (6 of 22) of the studies demonstrated moderate relative peritoneal uptake (12-37%). No studies demonstrated peritoneal uptake above 37%.

CONCLUSIONS

All patients had successful drug delivery of In-111-DTPA to the ventriculo-thecal space. 73% of the patients had minimal relative (< 12%) peritoneal drug uptake. Though efficacy varies by shunt model, low numbers preclude conclusions regarding model superiority. CSF flow scintigraphy studies assesses drug distribution of In-111-DTPA, informing CSF flow for delivery of intraventricular therapies.

Current Immunotherapeutic Approaches for Malignant Gliomas

Glioblastoma is the most common malignant central nervous system (CNS) tumor (48.3%), with a median survival of only about 14.6 months. Although the CNS is an immune-privileged site, activated T cells can cross the blood-brain barrier. The recent successes of several immunotherapies for various cancers have drawn interest in immunotherapy for treatment of malignant glioma. There have been extensive attempts to evaluate the efficiency of immunotherapy against malignant glioma. Passive immunotherapy for malignant glioma includes monoclonal antibody-mediated immunotherapy, cytokine-mediated therapy, and adoptive cell transfer, also known as chimeric antigen receptor T cell treatment. On the other hand, active immunotherapy, which stimulates the patient’s adaptive immune system against specific tumor-associated antigens, includes cancer vaccines that are divided into peptide vaccines and cell-based vaccines. In addition, there is immune checkpoint blockade therapy, which increases the efficiency of immunotherapy by reducing the resistance of malignant glioma to immunotherapy. Despite centuries of efforts, immunotherapeutic successes for malignant glioma remain limited. However, many clinical trials of adoptive cell transfer immunotherapy on malignant glioma are ongoing, and the outcomes are eagerly awaited. In addition, although there are still several obstacles, current clinical trials using personalized neoantigen-based dendritic cell vaccines offer new hope to glioblastoma patients. Furthermore, immune checkpoint targeted therapy is expected to decipher the mechanism of immunotherapy resistance in malignant glioma in the near future. More studies are needed to increase the efficacy of immunotherapy in malignant glioma. We hope that immunotherapy will become a new treatment of malignant glioma.

New phase therapeutic pursuits for targeted drug delivery in glioblastoma multiforme

Glioblastoma multiforme (GBM) is known as the most aggressive and prevalent brain tumor with a high mortality rate. It is reported in people who are as young as 10 years old to as old as over 70 years old, exhibiting inter and intra tumor heterogeneity. There are several genomic and proteomic investigations that have been performed to find the unexplored potential targets of the drug against GBM. Therefore, certain effective targets have been taken to further validate the studies embarking on the robustness in the field of medicinal chemistry followed by testing in clinical trials. Also, The Cancer Genome Atlas (TCGA) project has identified certain overexpressed targets involved in the pathogenesis of GBM in three major pathways, i.e., tumor protein 53 (p53), retinoblastoma (RB), and receptor tyrosine kinase (RTK)/rat sarcoma virus (Ras)/phosphoinositide 3-kinase (PI3K) pathways. This review focuses on the compilation of recent developments in the fight against GBM thus, directing future research into the elucidation of pathogenesis and potential cure for GBM. Also, it highlights the potential biomarkers that have undergone extensive research and have promising prognostic and predictive values. Additionally, this manuscript analyses the advent of gene therapy and immunotherapy, unlocking the way to consider treatment approaches other than, or in addition to, conventional chemo-radiation therapies. This review study encompasses all the relevant research studies associated with the pathophysiology, occurrence, diagnostic tools, and therapeutic intervention for GBM. It highlights the evolution of various therapeutic perspectives against GBM from the most conventional form of radiotherapy to the recent advancement of gene/cell/immune therapy. Further, the review focuses on various targeted therapies for GBM including chemotherapy sensitization, radiotherapy, nanoparticles based, immunotherapy, cell therapy, and gene therapy which would offer a comprehensive account for exploring several facets related to GBM prognostics.

Radioimmunotherapy for solid tumors: spotlight on Glypican-1 as a radioimmunotherapy target

Radioimmunotherapy (i.e., the use of radiolabeled tumor targeting antibodies) is an emerging approach for the diagnosis, therapy, and monitoring of solid tumors. Often using paired agents, each targeting the same tumor molecule, but labelled with an imaging or therapeutic isotope, radioimmunotherapy has achieved promising clinical results in relatively radio-resistant solid tumors such as prostate. Several approaches to optimize therapeutic efficacy, such as dose fractionation and personalized dosimetry, have seen clinical success. The clinical use and optimization of a radioimmunotherapy approach is, in part, influenced by the targeted tumor antigen, several of which have been proposed for different solid tumors. Glypican-1 (GPC-1) is a heparan sulfate proteoglycan that is expressed in a variety of solid tumors, but whose expression is restricted in normal adult tissue. Here, we discuss the preclinical and clinical evidence for the potential of GPC-1 as a radioimmunotherapy target. We describe the current treatment paradigm for several solid tumors expressing GPC-1 and suggest the potential clinical utility of a GPC-1 directed radioimmunotherapy for these tumors.

Detection of clinically silent brain lesions in [18F]FDG PET/CT study in oncological patients: analysis of over 10,000 studies

The study aimed to show that including the brain region into the standard 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography ([18F]FDG PET/CT) study protocol may result in detecting clinically silent brain tumours. We retrospectively analyzed the group of 10,378 from the total of 12,011 consecutive patients who underwent the torso and brain [18F]FDG PET/CT scanning, considering an ability of the method to evaluate undetected before brain tumours in patients diagnosed and treated in our institution. While collecting the database, we followed the inclusion criteria: at least 1-year of follow-up, a full medical history collected in our institution, histopathologic examination or other studies available to confirm the type of observed lesion, and the most importantly-no brain lesions reported in the patients' medical data. In this study, performing the torso and brain [18F]FDG PET/CT imaging helped to detect clinically silent primary and metastatic brain tumours in 129 patients, and the benign lesions in 24 studied cases, in whom no suspicious brain findings were reported prior to the examination. In conclusion, including the brain region into the standard [18F]FDG PET/CT protocol can be considered helpful in detecting clinically silent malignant and benign brain tumours.

Primary and Metastatic Brain Tumours Assessed with the Brain and Torso [18F]FDG PET/CT Study Protocol-10 Years of Single-Institutional Experiences

According to the international societies’ recommendations, the 2-deoxy-2-[¹⁸F]fluoro-D-glucose positron emission tomography/computed tomography ([¹⁸F]FDG PET/CT) technique should not be used as the method of choice in brain tumour diagnosis. Therefore, the brain region can be omitted during standard [¹⁸F]FDG PET/CT scanning. We performed comprehensive literature research and analysed results from 14,222 brain and torso [¹⁸F]FDG PET/CT studies collected in 2010–2020. We found 131 clinically silent primary and metastatic brain tumours and 24 benign lesions. We concluded that the brain and torso [¹⁸F]FDG PET/CT study provides valuable data that may support therapeutic management by detecting clinically silent primary and metastatic brain tumours.

Theranostics in Brain Tumors

Theranostic nuclear oncology, mainly in neuro-oncology (neurotheranostics), aims to combine cancer imaging and therapy using the same targeting molecule. This approach tries to identify patients who are most likely to benefit from tumor molecular radionuclide therapy. The ability of radioneurotheranostic agents to interact with cancer cells at the molecular level with high specificity can significantly improve the effectiveness of cancer therapy. A variety of biologic targets are under investigation for treating brain tumors. PET-based precision imaging can substantially improve the therapeutic efficacy of radiotheranostic approach in brain tumors.

Intracranial 131I-chTNT Brachytherapy in Patients with Deep-Seated Glioma: A Single-center Experience with 10-Year Follow-up from China

OBJECTIVE

 The intracranial brachytherapy has been applied for decades, however, no results with long-term follow-up have been reported. This study investigated the long-term efficiency of intra-tumoral injection of ¹³¹I-chTNT in patients with deep-seated glioma.

METHOD

 Thirty-five patients undergoing ¹³¹I-chTNT brachytherapy between December 2004 and May 2009 were enrolled. ¹³¹I-chTNT was injected at a dose of 1.5 mCi/cm³ at an interval of 1 month for consecutive 3 times. Serial ECT scan and MRI were performed during follow-up. Progression-free survival (PFS) and overall survival (OS) were analyzed. Adverse reactions were graded with WHO Toxicity Grading Scale for determining the severity of adverse events.

RESULTS

 ECT scan showed that enhanced accumulation of radioactive agents in the tumor lasted for more than 30 days. Three months after final injection, tumor complete remission (CR) was observed in 4 patients (11.4 %), partial remission (PR) in 11 cases (31.4 %), stable disease (SD) in 10 cases (28.6 %) and progressive disease (PD) in 10 cases (28.6 %). At 6-month, CR, PR, SD and PD were 2, 6, 12 and 15 respectively. After 10 years of follow-up, median progression-free survival (PFS) and overall survival (OS) were 5.4 and 11.4 months. One-year survival was 45.7 %, two and five-year survival was 8.6 %, ten-year survival was 5.7 %. Multivariate analysis showed that pathological grade and tumor diameter were independent prognostic factors for PFS and OS. Grade I-II adverse events occurred after drug injection, including nausea, fever, headache, hairloss and fatigue.

CONCLUSION

 ¹³¹I-chTNT intracranial brachytherapy is efficient and safe for patients with deep-seated glioma. It is a reliable option for inoperable glioma patients.