New Treatments for Malignant Gliomas: Careful Evaluation and Cautious Optimism Required

The treatment of patients with glioblastoma is a showcase for improved technology in many disciplines of medicine. Imaging technology has improved substantially, leading to more accurate and rapid diagnosis; better anatomic localization, which leads to improvements in neurosurgical results; and earlier detection of recurrent or relapsing disease. Surgical techniques have improved with better tumor delineation, which results in a higher percentage of patients having what seems to be complete tumor resection while maintaining or even improving neurologic function. Radiation therapy has also improved, beginning with the recognition that regional treatment is better than whole-brain radiation for most malignant primary brain tumors. Technological advances, such as conformal radiation and intensity-modulated radiation therapy, have resulted in more accurate delivery of treatment and therefore less collateral damage to normal neuronal structures. Many new chemotherapeutic agents have been developed and tested, and multicenter clinical trial groups have formed. However, until very recently, chemotherapy did not substantially improve outcomes when added to the other treatment methods.

Despite these advances in the process of care, patient outcomes have not changed very much. Even extensive surgical resection with documented removal of all visible tumor only prolongs survival by a few months. A study by Lacroix and colleagues (1) clearly showed that patients with glioblastoma who had greater than 98% resection fared better than patients whose tumors had less extensive resection (median survival, 13 months vs. 8.6 months). Although the outcome is better, patients having what the surgeon thinks is total resection have microscopic tumor infiltration into the surrounding brain, often detectable by obtaining a biopsy specimen several centimeters away. Similarly, radiation therapy clearly improves survival when compared with chemotherapy alone or with supportive care (2). However, with radiation after surgical resection, most studies show a median survival …