Trends in glioblastoma: outcomes over time and type of intervention: a systematic evidence based analysis

Introduction: Despite aggressive treatment with chemoradiotherapy and maximum surgical resection, survival in patients with glioblastoma (GBM) remains poor. Ongoing efforts are aiming to prolong the lifespan of these patients; however, disparities exist in reported survival values with lack of clear evidence that objectively examines GBM survival trends. We aim to describe the current status and advances in the survival of patients with GBM, by analyzing median overall survival through time and between treatment modalities. Methods: A systematic review was conducted according to PRISMA guidelines to identify articles of newly diagnosed glioblastoma from 1978 to 2018. Full-text glioblastoma papers with human subjects, ≥ 18 years old, and n ≥ 25, were included for evaluation. Results: The central tendency of median overall survival (MOS) was 13.5 months (2.3–29.6) and cumulative 5-year survival was 5.8% (0.01%–29.1%), with a significant difference in survival between studies that predate versus postdate the implementation of temozolomide and radiation, [12.5 (2.3–28) vs 15.6 (3.8–29.6) months, P < 0.001]. In clinical trials, bevacizumab [18.2 (10.6–23.0) months], tumor treating fields (TTF) [20.7 (20.5–20.9) months], and vaccines [19.2 (15.3–26.0) months] reported the highest central measure of median survival. Conclusion: Coadministration with radiotherapy and temozolomide provided a statistically significant increase in survival for patients suffering from glioblastoma. However, the natural history for GBM remains poor. Therapies including TTF pooled values of MOS and provide means of prolonging the survival of GBM patients.