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More extensive resection improves survival for patients with glioblastoma multiforme
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Gross total resection appeared to improve OS and PFS compared with subtotal resection in adults with glioblastoma multiforme, according to the results of a retrospective meta-analysis.
However, researchers reported the quality of supporting evidence in the meta-analysis was moderate to low.
“Glioblastoma multiforme is the most common malignant primary brain tumor in adults and is known for its invasive and aggressive behavior,” Timothy J. Brown, MD, resident at The University of Texas Southwest Medical Center, and colleagues wrote. “The unique anatomy of the brain and concern about injury to eloquent structures with resulting impairment on quality of life often make the goal of gross total resection difficult to attain.”
Previous data from retrospective cohort studies suggest patients with newly diagnosed glioblastoma multiforme experienced improved OS for extent of resection ranging from 78% to 98%. However, the optimum extent of tumor resection remains controversial, with conflicting results regarding efficacy and safety of aggressive resection.
Brown and colleagues sought to determine whether greater extent of tumor resection is associated with improved 1- and 2-year OS, as well as 6-month and 1-year PFS, in patients with glioblastoma multiforme.
Researchers searched PubMed, CINAHL and Web of Science to identify 37 relevant studies published between 1966 and 2015, representing 41,117 unique patients who underwent gross total resection, subtotal resection or biopsy.
Based on American Academy of Neurology level of evidence criteria — which rates studies from class 1 to 4, where class 1 is the strongest level of evidence — researchers determined these studies had evidence levels of class 2 (n = 4), 3 (n = 15) and 4 (n = 18). They then conducted a final quality assessment using Grading of Recommendations Assessment, Development, and Evaluation criteria and PRISMA guidelines and determined the level of evidence was moderate for OS and for meta-analyses including only class 2 studies, whereas the assessment was low for all other analyses.
The main outcomes included RR for mortality at 1 and 2 years and disease progression at 6 months and 1 year.
Results of the analysis showed gross total resection reduced the risk for mortality at 1 year (RR = 0.62; 95% CI, 0.56-0.69) and 2 years (RR = 0.84; 95% CI, 0.79-0.89) compared with subtotal resection.
Further, subtotal resection reduced the 1-year risk for mortality compared with biopsy (RR = 0.85; 95% CI, 0.8-0.91). The mortality risk decreased at 1 year (RR = 0.77; 95% CI, 0.71-0.84) and 2 years (RR = 0.94; 95% CI, 0.89-1) for any resection compared with biopsy.
Gross total resection also decreased risk for progression compared with subtotal resection at 6 months (RR = 0.72; 95% CI, 0.48-1.09) and 1 year (RR = 0.66; 95% CI, 0.43-0.99).
The researchers acknowledged that studies in the meta-analysis included differing prognostic variables, which may have resulted in confounding of data. Further, small studies that favored subtotal dissection or biopsy may have been lacking, thus leading to possible publication bias.
“This analysis represents the largest systemic review and only quantitative systemic review to date performed on this subject, researchers wrote. “We suggest . . . that gross total resection probably increases the likelihood of 1-year survival compared with subtotal resection by about 61% and increases the likelihood of 2-year survival by about 19%.” – by Nick Andrews
Disclo sure: The researchers report no relevant financial disclosures.
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