Treatment outcomes of Anti-angiogenic agent (Bevacizumab) in Glioblastoma patients: A rapid review

Introduction:

Glioblastomas constitute some of the most aggressive brain tumors known. They exhibit high mortality rates, and low survival rates. Additionally, owing to its location, it results in a range of neurologic, functional, and physical dysfunction within a relatively short period. Despite the administration of standard treatment, survival rates remain abysmally low. Recently, the use of anti-angiogenic agents such as Bevacizumab (BEV) as adjuncts for the treatment of glioblastomas was introduced. However, studies into its efficacy have been conflicting. Hence, there is need for synthesis of existing research findings to improve evidence-based decision making for the treatment of Glioblastomas.

Objectives:

This review aims to present an in-depth synopsis of high-level evidence on the outcomes of using BEV as adjuncts to standard therapy (Radiotherapy and Chemotherapy) on overall survival and progression free survival in individuals with recently or newly diagnosed Glioblastomas.

Methods: 

A search of the English literature using key terms for the disease/population of interest was executed in Embase (Embase.com), MEDLINE (PubMed) and The Cochrane Database of Systematic Reviews to identify relevant studies. Controlled vocabulary such as the National Library of Medicine’s MESH (Medical Subject Heading) in MEDLINE were used. For this study, the chemotherapeutic drug of interest was Temozolomide, thus when chemotherapy was used, only studies where Temozolomide was the chemotherapeutic agent was included. Overall survival and progression free survival were the main outcomes assessed.

Results:

Seven hundred and twenty-eight studies were identified through database search after removal of duplicates. From this, 10 full length articles which satisfied eligibility criteria were included in final analysis. Of the 10 studies, 5 reported both median and overall survival rates, an equal number reported overall survival, while 12 studies reported progression free survival rates. Varying reports and conclusions were made by the reports considered.

Conclusions:

The impact of BEV administration as an adjunct to standard treatment for glioblastoma differed between studies. However, the review indicate that the addition of BEV appears to improve PFS (not statistically significant). Conversely, there seems to be no significant impact on OS. TMZ and BEV combination also appears to improve tumour shrinkage considerably, but this may be at the expense of increased toxicity. More studies are needed to determine the optimal dosage, long term effects, and duration.