Glioblastoma, an aggressive cancer that takes the form of fast-growing primary brain tumors, is commonly treated with a combination of surgery, chemotherapy, and radiation. Radiation specifically is known to increase survival among glioblastoma patients — however 30 percent of patients do not receive this type of treatment. Why is this, and what effect does it have on overall glioblastoma outcomes? A multi-disciplinary team at the University of Kentucky and the University of Illinois at Chicago sought to answer these questions. The resulting publication appears in the journal Medical Oncology.
Investigators worked to identify characteristics associated with not receiving radiation and the impact on glioblastoma outcomes. They analyzed the Surveillance, Epidemiology, and End Results program (SEER) registries database for the years 2000-2013, reviewing 30,479 glioblastoma cases occurring in patients age 20 and older. Of these patients, 21,179 received radiation as first course of therapy, while 8,218 did not. Among those who did not receive radiation, with 5,178—63 percent—were age 65 and older. Early decisions on surgery often predicted radiation therapy, with 61 percent having only a biopsy — or no surgery — at diagnosis. Although radiation use as upfront therapy for glioblastoma slowly increased over the 13-year study period at a rate of 0.4 percent per year; still 25 percent did not receive radiation in 2013.
The investigators found that patients treated with radiation were likely to be younger, to have undergone surgery, to live in a metropolitan area, to have higher socioeconomic status, and to be in a couple-based relationship. Increased survival was associated with the use of upfront radiation along with factors including: younger age, being of race other than white, undergoing surgery, and a more recent diagnosis. The study also found that not receiving radiation therapy adversely affected survival. Decreased usage of radiation in the elderly and in biopsy-only surgeries was anticipated, but race, gender, and poverty were also statistically significant. Overall, investigators observed a trend toward an increased use of radiation, although many young adults still do not receive this potentially survival-increasing treatment.
“Clinicians should be aware of this underutilization, and an increased usage of radiation should improve outcomes for glioblastoma,” the authors conclude.
Authors of “Characteristics and survival outcomes associated with the lack of radiation in the treatment of glioblastoma,” are Dr. Bin Huang University of Kentucky College of Public Health Division of Cancer Biostatistics and Markey Cancer Center; Dr. Therese A. Dolecek, University of Illinois at Chicago School of Public Health; Dr. Quan Chen, UK College of Public Health Division of Cancer Biostatistics and Markey Cancer Center; Dr. Catherine R. Garcia, Markey Cancer Center; Dr. Thomas Pittman, UK College of Medicine and Markey Cancer Center; and Dr. John L. Villano, UK College of Medicine and Markey Cancer Center.