Patients who were suspected to have glioma were given a drink containing the chemical 5-ALA which is known to accumulate in fast growing cancer cells. The pink glow that the chemical causes was found in patients with the most aggressive cancers, it is hoped that this will make it easier for surgeons to distinguish between cancer cells and healthy brain tissues.
Glioma is the most common form of brain cancer, treatment typically involves surgery to remove as much of the cancer as possible, unfortunately prognosis is often poor.
99 patients with suspected high grade gliomas were enrolled in this study who were given 5-ALA to drink before undergoing surgery. 5-ALA has been shown in previous studies to end up in fast growing cancer cells as they lack enzymes needed to break the chemical down.
UV microscopes were used during surgery to help look for fluorescent tissue while removing tumours from patient brains; surgeons reported seeing fluorescence in 85 of the patients during their operations. 81 out of these were confirmed to have high grade disease, 1 was found to have low grade disease, and 3 could not be assessed by pathologists. In the 14 patients that fluorescences were not seen 7 tumours were found to be low grade, and the other 7 could not be assessed.
Neurosurgeons need to have something while the patient is on the table to help guide them to find as much of the worst bits possible, the beauty of 5-ALA is that it enables surgeons to see where the high grade glioma is while operating to remove it, says Dr. Kathreena Kurian.
This study only looked at those who were already suspected to have high grade tumours, larger studies involving more subjects with low grade disease would help to provide more information on the use of this technique as other types of markers may be need to be tested for detecting low grade glioma cells.
Next phase of 5-ALA studies may involve testing in children with brain tumours, or to help surgeons distinguish between tumour tissues and scar tissues in adult patients with recurring brain cancer. Fluorescent marker may help to ease the burden of follow up as cancer cells remaining after surgery will require additional radiotherapy or chemotherapy.
5-ALA was approved in 2018 for use in patients with brain tumours prior to surgery by the National Institute for Health and Clinical Excellence, research will be presented at the 2018 NCRI Cancer Conference in Glasgow.
