Radiation therapy (RT) is an integral component of the management of brain tumors, but cognitive deficits following cranial irradiation are well documented. There is an association between damage to neural progenitor cells (NPC) and neurocognitive dysfunction. NPC are similarly known to play an important role in recovery from damage to the brain, including radiation-induced damage. However NPC are extremely sensitive to radiation. In spite of this information, current RT planning techniques do not limit the radiation dose to the NPC containing regions. Recent human studies have demonstrated that it is possible to use intensity modulated radiation therapy to reduce the radiation dose to NPC containing regions during RT for brain tumors, without compromising coverage of the tumor. We hypothesize that NPC-sparing RT will reduce neurocognitive decline following treatment for brain tumors, without compromising tumor local control. However, there is conflicting data regarding the role of NPC in the development of glioblastoma multiforme (GBM). Some studies suggest that GBM are derived from NPC whereas others have associated NPC with improved tumor control following therapy for GBM. Prior to evaluation of neurocognitive outcomes with NPC-sparing RT, it is therefore imperative to evaluate whether NPC-sparing RT techniques lead to increased LR in the spared NPC containing niches of the brain.~The proposed study is designed to evaluate LR in the spared regions of the brain following NPC sparing RT in patients with newly diagnosed GBM. Our research will consist of 3 specific aims: 1) Determine the LR rate at 1 year in the spared NPC containing niches in patients treated with NPC sparing RT for GBM; 2) Quantify the extent of radiation dose sparing to the NPC containing regions that is possible without compromising tumor coverage in patients with GBM; 3) Determine if it is feasible to evaluate cognitive function prospectively in patients undergoing NPC sparing RT for GBM.~The long term goal of this research is to establish whether NPC sparing RT techniques improve neurocognitive outcomes compared to conventional RT for brain tumors. If the proposed study demonstrates that NPC sparing RT is not associated with increased LR in the spared regions of the brain compared to conventional RT, it will ideally serve as the foundation for a future multi-institutional randomized controlled trial comparing neurocognitive outcomes in patients treated with NPC-sparing RT versus conventional radiation therapy.
The long term goal of this research is to establish whether NPC sparing RT techniques improve neurocognitive outcomes compared to conventional RT for brain tumors. If the proposed study demonstrates that NPC sparing RT is not associated with increased LR in the spared regions of the brain compared to conventional RT, it will ideally serve as the foundation for a future multi-institutional randomized controlled trial comparing neurocognitive outcomes in patients treated with NPC-sparing RT versus conventional radiation therapy.