Intratumoral Hydrogen Peroxide Injection During Meningioma Resection

Preoperative meningioma vascularity index is associated with significantly increased intraoperative blood loss and greater risk of subtotal resection

OBJECTIVE

Surgical recovery of meningiomas relies on a variety of factors, including tumor volume, vascularity, embolization status, and blood loss during excision. Although hypervascular meningiomas can potentially be amendable to embolization, methods for determining optimal vascularity for this procedure are currently lacking. Our group previously established the meningioma vascularity index (MVI) as a marker of tumor vascularity. In this study, we aim to build on our previous work and further examine the relationship between MVI and intraoperative estimated blood loss (EBL).

METHODS

A retrospective data extraction was conducted between August 2010 and October 2019 from patients undergoing craniotomy for meningioma. Of the 85 intracranial meningiomas included, 39 were embolized. Demographic data, extent of resection, embolization status, and EBL were among the extracted variables. Flow void volumes were measured on T2-weighted MRI images using a segmentation software with a voxel-based segmentation method.

RESULTS

MVI was a predictor of EBL within the entire cohort, when controlling for tumor volume (R² adjusted = 0.26; P = 0.027). A high MVI (> 2.01 cm³) was associated with higher likelihood of receiving subtotal resection (STR) (OR 4.07, 95% CI 1.17-14.15; P = 0.035). Although the mean MVI and tumor volume were higher in the embolized cohort (P = 0.009 and P = 0.005), there were no significant differences in EBL, or blood transfusion rates regardless of embolization status.

CONCLUSIONS

MVI may be used as a non-invasive radiological marker to gauge meningioma vascularity, predict EBL, and guide the decision-making process when it comes to embolization and surgical planning.

Intratumoral pro-oxidants promote cancer immunotherapy by recruiting and reprogramming neutrophils to eliminate tumors

Neutrophils have recently gained recognition for their potential in the fight against cancer. Neutrophil plasticity between the N1 anti-tumor and N2 pro-tumor subtypes is now apparent, as is the ability to polarize these individual subtypes by interventions such as intratumoral injection of various agents including bacterial products or pro-oxidants. Metabolic responses and the production of reactive oxygen species (ROS) such as hydrogen peroxide act as potent chemoattractants and activators of N1 neutrophils that facilitates their recruitment and ensuing activation of a toxic respiratory burst in tumors. Greater understanding of the precise mechanism of N1 neutrophil activation, recruitment and regulation is now needed to fully exploit their anti-tumor potential against cancers both locally and at distant sites. This systematic review critically analyzes these new developments in cancer immunotherapy.

Histopathological changes of neuronal tissue following the use of hydrogen peroxide in neurosurgical procedures

Background:

Hydrogen peroxide (HP) is routinely used in neurosurgical procedures to achieve surgical hemostasis. However, its safety profile is still debatable with various reports depicting range of adverse effects on neuronal tissue. The objective of this paper is to evaluate the safety and efficacy of HP as a hemostatic agent in normal neuronal tissue during neurosurgical procedures conducted on rats.

Methods:

One hundred rats were divided into three groups. The first and third group underwent cortical irrigation with HP and the second group underwent spinal irrigation with HP. All groups were irrigated with different concentrations of HP (1%, 3%, or 6%) for 3 min and tissue biopsies were obtained immediately afterwards (Groups A and B) or 1 week after HP irrigation (Group C). Study specimens were examined histologically and compared to control tissue.

Results:

All rats showed normal behavioral, functional, and motor neurological activity following the procedures. Histopathologically, dark neurons were observed in all HP exposed tissue. The cytoplasm revealed condensed and dark Nissl substance and the neurites and axons exhibited a corkscrew morphology. No ischemic changes or inflammatory infiltrates were detected. The majority of dark neurons were observed at the periphery of tissue fragments. These findings were present and consistent in both the short- and long-term groups.

Conclusion:

HP irrigation showed no significant short- or long-term clinical and histopathological changes in comparison to normal saline when used on rats’ neuronal tissue. This may confirm the safety of intraoperative HP usage as hemostatic agent during neurosurgical procedures.

Mobilization of the outer cavernous membrane decreases bleeding and improves resection in spheno-clinoidal meningiomas without cavernous sinus extension: A randomized controlled trial

Objective

The aim of this study was to determine whether adding mobilization of the outer cavernous sinus membrane as a part of the approach, in large spheno-clinoidal meningiomas without cavernous sinus extension, would reduce bleeding and increase the extent of resection.

Methods:

This prospective randomized controlled trial was held between February 2016 and April 2017 at Cairo University Hospitals. The study recruited 94 patients with spheno-clinoidal meningiomas without cavernous sinus involvement. Patients were randomly assigned (by a computer based randomization system) into two groups; the treatment group, in which the patients received mobilization of the outer layer of the lateral wall of the cavernous sinus, prior to opening of the dura; and, the control group, in which the patients were operated by a direct opening of the dura without cavernous sinus dissection. The primary outcome of this study was the difference in the amount of blood lost during surgery between both groups of patients. The secondary outcome variables were the estimated blood loss (EBL) calculated according to Mercurelli's formula, the extent of tumor resection and the amount of blood transfused.

Results:

The amount of blood loss and estimated blood loss (EBL) were significantly less in the "with mobilization group" with the P value being 0.00 and 0.013, respectively. Additionally, the amount of residual tumor was compared between both the groups and it showed that the group of patients who have received mobilization of the outer cavernous sinus membrane had a higher rate of radical resection as expressed by a lower volume of residual tumor (P value 0.005).

Conclusion:

In large spheno-clinoidal meningiomas without cavernous sinus involvement, routine mobilization of the outer cavernous sinus membrane reduces bleeding. This helps in a better visualization of cranial nerves in a relatively avascular field as it enables the performance of neurovascular dissection in an earlier phase of surgery. It also enables a more radical resection.

Paradigm Shift in Radiation Biology/Radiation Oncology-Exploitation of the "H₂O₂ Effect" for Radiotherapy Using Low-LET (Linear Energy Transfer) Radiation such as X-rays and High-Energy Electrons

Most radiation biologists/radiation oncologists have long accepted the concept that the biologic effects of radiation principally involve damage to deoxyribonucleic acid (DNA), which is the critical target, as described in "Radiobiology for the Radiologist", by E.J. Hall and A.J. Giaccia [1]. Although the concepts of direct and indirect effects of radiation are fully applicable to low-LET (linear energy transfer) radioresistant tumor cells/normal tissues such as osteosarcoma cells and chondrocytes, it is believed that radiation-associated damage to DNA does not play a major role in the mechanism of cell death in low-LET radiosensitive tumors/normal tissues such as malignant lymphoma cells and lymphocytes. Hall and Giaccia describe lymphocytes as very radiosensitive, based largely on apoptosis subsequent to irradiation. As described in this review, apoptosis of lymphocytes and lymphoma cells is actually induced by the "hydrogen peroxide (H₂O₂) effect", which I propose in this review article for the first time. The mechanism of lymphocyte death via the H₂O₂ effect represents an ideal model to develop the enhancement method of radiosensitivity for radiation therapy of malignant neoplasms. In terms of imitating the high radiosensitivity of lymphocytes, osteosarcoma cells (representative of low-LET radioresistant cells) might be the ideal model for indicating the conversion of cells from radioresistant to radiosensitive utilizing the H₂O₂ effect. External beam radiation such as X-rays and high-energy electrons for use in modern radiotherapy are generally produced using a linear accelerator. We theorized that when tumors are irradiated in the presence of H₂O₂, the activities of anti-oxidative enzymes such as peroxidases and catalase are blocked and oxygen molecules are produced at the same time via the H₂O₂ effect, resulting in oxidative damage to low-LET radioresistant tumor cells, thereby rendering them highly sensitive to irradiation. In this review, this potential paradigm shift in modern radiation biology/radiation oncology is discussed in detail in terms of overcoming drug/radiation resistance in radiation therapy and/or anti-cancer chemotherapy.

Development of a novel enzyme-targeting radiosensitizer (KORTUC) containing hydrogen peroxide for intratumoral injection for patients with low linear energy transfer-radioresistant neoplasms

The therapeutic effect of radiotherapy using linear accelerators for relatively large tumors of more than several centimeters in diameter is reduced to one third due to a large number of hypoxic tumor cells and a significant amount of anti-oxidative enzymes including peroxidase/catalase. The most effective method by which to inject hydrogen peroxide into tumor tissue was examined. This proved difficult as 3% w/v hydrogen peroxide solution (Oxydol) is an antiseptic agent for skin lesions. Thus, injection into an affected lesion may result in hydrogen peroxide soaking into a body cavity, possibly causing an intra-arterial oxygen embolism. This study aimed to identify the most effective combination of drugs containing hydrogen peroxide in order to relieve local pain at the injection site and preserve high intratumoral oxygen concentration. Hyaluronate-hydrogen peroxide was identified as the most effective combination of drugs containing hydrogen peroxide for the preservation of high intratumoral oxygen concentration for 24 h following intratumoral injection with the agent. Based on the results, the clinical application of a novel enzyme-targeting radiosensitization treatment, Kochi Oxydol-Radiation Therapy for Unresectable Carcinomas (KORTUC), was initiated for malignant tumors including advanced breast cancer, soft tissue sarcoma and cervical lymph node metastasis. Moreover, we have developed KORTUC III for locally advanced hepatocellular carcinoma and KORTUC IV for locally advanced pancreas cancer (stage IVa).