Introduction and Background

Abstract

Glioblastoma (GB) accounts for 54 % of primary brain tumors, with an incidence of about fi ve new cases for every 100,000 per year, and after aggressive multimodal treatments, prognosis remains poor, with a 5-year Overall Survival (OS) rate barely reaching 5 %, as extensively documented in the section of this book dedicated to prognostic parameters of GB. Maximum achievable safe surgical resection, and limited-volume radiotherapy (RT) with concurrent and sequential chemotherapy (CHT) based on the alkylating agent Temozolomide (TMZ) [ 1 ], achieve 40, 15, and 7-8 % OS rates, respectively at 1-, 2-, and 3-years. These present standards of treatment mostly stem from studies dating back to the seventies of the last century [ 2 , 3 ], and progressively evolving through subsequent clinical trials.A great deal of medical literature is dedicated to GB, with increasing frequency over time. Most recent articles on GB, in fact, begin with the statement that prognosis has not improved, despite the numerous research fi ndings on its underlying genomic and molecular mechanisms. This is due at least in part to the diffi culty in improving patient outcomes, given the elusive nature of this disease with respect to therapeutic innovations, including those in the RT domain. Radiation is one of the most used and useful tool against cancer, including GB, and knowledge of its mechanisms of action on biological substrates is of the utmost importance in oncology. Radioresistance of GB is one challenge for Radiation Biology (RB) that has emerged from the clinical setting, and important questions raised by clinical experiences are addressed by basic RB laboratory research. However, RB is a scarcely known discipline outside of the inner circle of the radiological science scholars, and we are convinced that a comprehensive and updated coverage of this subject is warranted, that is, the aim of this book. The researchers and the practitioners studying GB in the domains of radiation and medical oncology, pathology, biology, and physics may profi t from reciprocal scientifi c contributions collected in a lineup fi tting the present state-of-the-art. 2We dedicated the fi rst section of the book to RB topics emerging from clinical studies on GB. These include research regarding RT dose, volume and fractionation, CHT associated with RT, RT modalities alternative to the current photon irradiation, mathematical modeling of treatment parameters, prognostic parameters and markers, and radiation tolerance of normal brain. The second part addresses preclinical research domains of particular relevance for GB. These include related basic experimental RB; immune system and GB microenvironment; genetic and epigenetic determinants in tumor initiation and progression; GB microenvironment in its relationship with hypoxia and glioma stem cellrelated radiation resistance; cell-death pathways and radiation; miRNA manipulation in modifying radiation resistance of GB; and nanoparticle research. The third and last section of the book deals with translational issues,...

Imaging Role in Diagnosis, Prognosis, and Treatment Response Prediction Associated with High-grade Glioma

“…[ 48 ] Therefore, it is necessary to use other imaging modalities and techniques as a complement to CT scan for its defects. [ 49 ]…”

“…MRS can be used to distinguish normal brain tissue from tumor, glioma from noninfiltrative tumor such as metastases, and also to determine tumor grade. [ 49 72 73 ]…”

“…GBM illustrates a growth in the ratio of Cho/NAA. [ 19 49 74 75 ] Furthermore, creatine (Cr) is a marker of normal cellular metabolism. Lactate, lipid, and myo-inositol (MI) reflect hypoxia, necrosis, and astrocyte integrity, respectively.…”

“…[ 8 ] Tracers including 11 C-MET and 18 FET are more useful than 18 F-FDG and are most widely used. [ 49 ] 11 C-MET and 18 FET are preferable for diagnosis of glioma in areas of infiltrating tumor cells that are not visualized by MRI. [ 4 ] It has been shown that using 18 FET data for RT planning compared to conventional methods increases the treatment volumes.…”