New light on the brain: The role of photosensitizing agents and laser light in the management of invasive intracranial tumors

Invasive intracranial tumors, particularly malignant gliomas, are very difficult to eradicate surgically and carry a dismal prognosis. The vast majority relapse locally indicating that their cure is dependent on radical and complete local excision. However, their ability to invade and hide among normal brain tissue, our inability to visualize and detect them, the low tolerance of brain tissue to ionizing radiation and the presence of the blood brain barrier are the main causes of our failure to eradicate them. Photodynamic detection with 100% specificity and more than 80% sensitivity offers an excellent chance of visualizing camouflaged tumor nests. Also, photodynamic therapy offers a very good chance of targeted destruction of the remaining tumor cells safely following surgical excision and may double the survival of patients harboring these awful tumors. More work needs to be done to refine this promising technology to exploit it to its full potential.