The FDA recently approved a dye that can accumulate in cancer cells and make them glow during brain surgery. This is a major advance especially for aggressive brain cancers called gliomas. Glioblastoma is the most aggressive and lethal glioma. Aggressive surgical removal of the tumor followed by chemotherapy and radiation are standards of care treatment. The major challenge with removing gliomas is that the cancer cells extend way beyond the confines of what the surgeons might appreciate as the main tumor. Hence, although the main tumor mass could be safely removed, the other cancer cells that are beyond the extent of the tumor mass are often left behind. These cells will continue to grow and eventually kill the patient. With the dye, surgeons can visualize cancer cells as they glow. This can have a major impact on the patient’s outcome since surgeons are now able to remove as much deadly cancer cells as possible with the assistance of this new dye.
The dye is called 5-ALA which is short for 5-Amino-Levulinic Acid. Cancer cells especially gliomas can take-up this dye and convert it into a substance that glows or has fluorescence. Surgeons can then use a microscope with fluorescent capabilities to visualize cancer cells and remove them while sparing normal brain tissue. Prior to 5-ALA, it was quite challenging to identify these cancer cells that blend with healthy brain tissue. A major limitation was then the risk of damaging vital and critical brain tissue with aggressive surgery.
It should be noted that 5-ALA has been extensively studied in Europe where it has been approved for clinical use for many years. In the original randomized trial published in the Lancet Journal over a decade ago, 5-ALA improved visualization of tumor and as a result, patients had excellent progression-free survival.
With the dye approved in the US, there is now hope for patients with aggressive gliomas. Prior to surgery, patients are given an oral solution of the dye which accumulates in cancer cells. Using a fluorescent microscope, the surgeon can identify cancer cells as they glow and remove them.
BBC has an interesting article on the successful application of 5-ALA in gliomas in the UK. In a recent study, researchers showed that the dye was very instrumental in guiding surgeons during brain tumor removal.
Below are some relatively newer studies on 5-ALA published and archived in the US National Library of Medicine: