'Fluorescent marker' could help surgeons remove deadly brain tumours
Fluorescent marker could be used to boost survival from one of the deadliest form of brain tumours.
Scientists found that using a chemical to highlight cancerous cells meant that they were able to identify the most aggressive types of disease, and to ensure that healthy brain tissue was not harmed.
The study, presented at the National Cancer Research Conference in Glasgow, involved 99 patients suffering from suspected glioma.
The disease, which killed former Labour cabinet minister Dame Tessa Jowell, is the most common form of brain cancer, with more than 2,200 cases diagnosed each year in England.
Treatment usually involves surgery to remove as much of the cancer as possible, but it can be difficult for surgeons to identify all of the cancer cells while avoiding healthy brain tissue.
Research on 99 patients found that the markers were able to detect the fastest growing tumours, and to improve the accuracy of subsequent surgery.
Scientists used a compound called 5-aminolevulinic acid or 5-ALA, which glows pink when a light is shone on it. Previous research shows that, when consumed, 5-ALA accumulates in fast growing cancer cells and this means it can act as a fluorescent marker of high-grade cells.
The study involved patients with suspected high-grade gliomas treated at the Royal Liverpool Hospital, Kings College Hospital in London and Addenbrooke’s Hospital in Cambridge.
Before surgery to remove their brain tumours, each patient was given a drink containing 5-ALA, and assessed for signs of fluorescence.
Surgeons then used operating microscopes to look for fluorescent tissue while removing tumours.
It was found in 85 cases, of which 81 were confirmed to be suffering from high-grade disease.
In the 14 cases where fluoresence was not seen, seven tumours were subsequently found, but all were low-grade disease, which grows far more slowly.
Scientists said the findings could extend survival for some of the deadliest forms of brain cancer, which often means patients only live months after diagnosis.
Lead researcher Colin Watts, Professor of Neurosurgery and chair of the Birmingham brain cancer programme at the University of Birmingham, said: “Neurosurgeons need to be able to distinguish tumour tissue from other brain tissue, especially when the tumour contains fast-growing, high-grade cancer cells. This is the first prospective trial to show the benefits of using 5-ALA to improve the accuracy of diagnosing high-grade glioma during surgery. These results show that the marker is very good at indicating the presence and location of high-grade cancer cells.”
“The advantage of this technique is that it may highlight more quickly high-grade disease within a tumour during neurosurgery. What this means is that more of the tumour can be removed more safely and with fewer complications, and that’s better for the patient.”
Professor Anthony Chalmers, chairman of NCRI’s Clinical and Translational Radiotherapy Research Working Group said there was a “desperate” need for better treatments for brain tumours, and said he hoped the technique could extend lives.
“The benefit of using a fluorescent marker is that it helps neurosurgeons see more accurately where the high-grade cancer is within the brain, in real time. In treating cancer, we are trying to improve survival by tailoring treatments to each individual patient. This technique provides on-the-spot information to help surgeons tailor the operation according to the location, size and grade of the tumour. We know that patients who have near total removal of their tumour have better outcomes, so we are optimistic that, in the long term, these new data will help to increase survival times for glioma patients,” he said.
