Phase II Trial of Low-Dose Whole Brain Radiotherapy With Concurrent Temozolomide and Adjuvant Temozolomide in Patients With Newly-Diagnosed Glioblastoma Multiforme

Study Summary

In the current proposed trial the role of the low-dose WBRT (0.15 Gy) would be to safely treat the microscopic distant GBM cells outside of the high dose RT region and sensitize the gross tumor, while the focal radiation dose (1.85 Gy) to the gross tumor will bring the total tumor dose of 2 Gy per fraction which is the standard of care. Radiotherapy (RT) has been integral in the treatment of GBM since the 1970s when Walker et al. showed that post-operative whole brain radiotherapy (WBRT) offered significant improvements in median survival time, and even more so when given with concomitant BCNU chemotherapy. Ensuing dose escalation studies found the optimal dose to be 60 Gy. Patients could not tolerate escalation to higher doses than 60 Gy with WBRT due to unacceptable toxicity. Even with WBRT of 60 Gy, a huge volume of healthy brain tissue was unnecessarily treated with high-dose radiation; recurrences with WBRT remained overwhelmingly local. Hochberg and Pruitt (1980) found that after WBRT only 3% of recurrences were outside 2 cm of the margins of the primary tumor. With the rise of the CT scan in the 1980s and the MRI in the 1990s, along with subsequent improvements in three-dimensional conformal radiation, partial brain RT (PBRT) became practical since tumor margins could be visualized and irradiated more accurately. - Subsequently, WBRT was shown to provide no survival benefit over PBRT at the same dosage; - thus, the latter took over as the standard of care.

Interventions

• RADIATION Radiation therapy
• DRUG Chemotherapy with Temodar.