Radiat Oncol J.  2019 Mar;37(1):13-21. 10.3857/roj.2019.00017.

National trends in radiation dose escalation for glioblastoma

• Wegner RE
• Abel S
• Horne ZD
• Hasan S
• Verma V
• Ranjan T
• Williamson RW
• Karlovits

• KMID: 2447547
• DOI: http://doi.org/10.3857/roj.2019.00017

Abstract

PURPOSE
Glioblastoma (GBM) carries a high propensity for in-field failure despite trimodality management. Past studies have failed to show outcome improvements with dose-escalation. Herein, we examined trends and outcomes associated with dose-escalation for GBM.
MATERIALS AND METHODS
The National Cancer Database was queried for GBM patients who underwent surgical resection and external-beam radiation with chemotherapy. Patients were excluded if doses were less than 59.4 Gy; dose-escalation referred to doses ≥66 Gy. Odds ratios identified predictors of dose-escalation. Univariable and multivariable Cox regressions determined potential predictors of overall survival (OS). Propensity-adjusted multivariable analysis better accounted for indication biases.
RESULTS
Of 33,991 patients, 1,223 patients received dose-escalation. Median dose in the escalation group was 70 Gy (range, 66 to 89.4 Gy). The use of dose-escalation decreased from 8% in 2004 to 2% in 2014. Predictors of escalated dose were African American race, lower comorbidity score, treatment at community centers, decreased income, and more remote treatment year. Median OS was 16.2 months and 15.8 months for the standard and dose-escalated cohorts, respectively (p = 0.35). On multivariable analysis, age >60 years, higher comorbidity score, treatment at community centers, decreased education, lower income, government insurance, Caucasian race, male gender, and more remote year of treatment predicted for worse OS. On propensity-adjusted multivariable analysis, age >60 years, distance from center >12 miles, decreased education, government insurance, and male gender predicted for worse outcome.
CONCLUSION
Dose-escalated radiotherapy for GBM has decreased over time across the United States, in concordance with guidelines and the available evidence. Similarly, this large study did not discern survival improvements with dose-escalation.

Keyword

GBM; Radiation therapy; Dose escalation; NCDB

MeSH Terms

Bias (Epidemiology)
Cohort Studies
Comorbidity
Continental Population Groups
Drug Therapy
Education
European Continental Ancestry Group
Glioblastoma*
Humans
Insurance
Male
Odds Ratio
Radiotherapy
United States