Fluorescent marker can help surgeons more precisely eliminate cancer cells from dangerous brain tumors

A chemical highlighting the tumor cells has been used by surgeons to help screen for brain cancer as part of a trial presented at the CNRI's cancer conference in 2018.

The research was conducted among patients with suspected glioma, the disease that killed Lady Tessa Jowell, and the most common form of brain cancer. Treatment usually involves surgery to eliminate cancer as much as possible, but surgeons may have difficulty identifying all cancer cells while avoiding healthy brain tissue.

The researchers say that using the fluorescent marker helps surgeons distinguish the most aggressive cancer cells from other brain tissues and hopes that this will ultimately improve the patient's survival.

The research was presented by Ms Kathreena Kurian, Reader and Associate Professor of Brain Tumor Research at the University of Bristol and Neuropathologist Consultant at the North Bristol NHS Trust in the UK. The study was led by Colin Watts, professor of neurosurgery and chair of the Birmingham Brain Cancer Control Program at the University of Birmingham, UK.

Dr. Kurian explained, "Gliomas are difficult to treat, their duration of survival often being measured in months rather than years, many patients undergo surgery and the goal is to safely eliminate them. As many cancers as possible, it is transmitted to a pathologist who examines the cells under the microscope to determine whether they are fast-growing "high-grade" cells or "low-quality" slow-growing cells. plan for further treatment, such as radiotherapy or chemotherapy, based on this diagnosis.

"We wanted to see if using a fluorescent marker could help surgeons objectively identify high-grade tumor cells during surgery, allowing them to remove as much cancer as possible while leaving intact normal brain tissue. "

The researchers used a compound called 5-aminolevulinic acid or 5-ALA, which glows pink when a light is on. Previous research has shown that when consumed, 5-ALA accumulates in rapidly growing cancer cells, which means that it can act as a fluorescent marker for high-grade cells.

The study focused on patients suspected of having high-grade gliomas treated at the Royal Liverpool Hospital, Kings College Hospital in London or at Addenbrooke Hospital in Cambridge, UK. -United. They were 23 to 77 years old and had a mean (median) age of 59 years. Before surgery to remove their brain tumors, each patient received a glass containing 5-ALA.

Surgeons then used operative microscopes to help them search for fluorescent tissue while removing brain tumors from patients. The collected tissue was sent to the pathology laboratory where scientists were able to confirm the accuracy of the surgeons' work.

A total of 99 patients received the 5-ALA marker and could be evaluated for signs of fluorescence. During their operations, surgeons found fluorescence in 85 patients. Pathologists subsequently confirmed that 81 of them had high grade disease. One case was low grade and three others could not be assessed.

Of the 14 patients for whom the surgeons saw no fluorescence, only seven tumors could subsequently be evaluated by pathology, but in all these cases, a low grade disease was confirmed.

Professor Watts said, "Neurosurgeons must be able to distinguish tumor tissue from other brain tissue, especially when the tumor contains fast-growing, high-grade cancer cells." This is the first prospective trial to be performed. show the benefits of using 5-ALA improve the accuracy of diagnosis of high grade gliomas during a surgical procedure: these results show that the marker is very good for indicating the presence and location of high grade cancer cells.

"The advantage of this technique is that it helps to more rapidly highlight a high-grade tumor in a tumor during neurosurgery.This means that a larger part of the tumor can to be removed more safely and with fewer complications, and that it is better for the patient. "

The researchers warned that the study involved patients who were already suspected of a high-grade tumor, and that a larger study in which more patients had low-grade disease would provide more information. Information on the use of this technique. They say that other types of markers may need to be tested to detect low grade glioma cells.

Next steps could include testing 5-ALA in children with brain tumors or helping surgeons distinguish tumor tissue from scar tissue in adult patients whose brain cancers have recurred after treatment.

Professor Anthony Chalmers is Chair of the CNRI Clinical and Translational Radiation Therapy Research Working Group and Chair of Clinical Oncology at the University of Glasgow, UK, and has not participated in the research. He said: "There is an urgent need for better treatments for brain tumors and to achieve this, we need more high quality research in this area.

"The advantage of using a fluorescent marker is that it helps neurosurgeons to see more precisely where the high-grade cancer in the brain is, in real time. In the treatment of cancer, we try to improve survival by adapting the treatments to each patient. This technique provides field information to help surgeons tailor the operation to the location, size and grade of the tumor. We know that patients who are almost completely removed from the tumor get better results, so we are optimistic. In the long term, these new data will help increase the survival time of patients with glioma. "

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