Results of a large meta-analysis suggest that gross total resection (GTR), as compared to subtotal resection (STR), improves survival in glioblastoma multiforme (GBM).
While GBM is the most common primary brain tumor found in adults, the best combination of surgical resection, radiation, and medical therapy for improved survival is not well established. GBM often presents as a difficult case, with cancer often found in both hemispheres of the brain and more than 1 lobe. Surgeons, therefore, are faced with achieving a difficult balance of risk and benefit in aggressive resections.
To examine the association between survival and the extent of GBM tumor resection, Timothy Brown, MD, of the University of Texas Southwestern Medical Center in Dallas, and colleagues conducted a meta-analysis, ultimately identifying 37 studies published between 1966 and 2015 that involved 41 117 patients with new diagnosis of supratentorial GBM treated with various degrees of resection, including STR and GTR and analysis of progression-free and overall survival.
Overall survival was found to be improved with GTR compared to STR at both 1 year (RR 0.62, 95% CI: 0.56-0.69, P<.001, NNT 9) and 2 years (RR 0.84, 95% CI: 0.79-0.89, P<.001, NNT 17) post-resection. Likewise, overall survival was improved with STR vs biopsy at 1 year (RR 0.85, 95% CI: 0.81-0.91, P<.001) but not at 2 years. When the data was combined, any resection was associated with improved survival at 1 year (RR 0.77, P<.001, NNT 21) and 2 years (RR 0.94, P=.04, NNT 593) compared to biopsy.
Eight studies were available to analyze data for disease progression. The investigators found a nonsignificant relative risk of 0.72 for GTR compared to STR (P=0.12, NNT 14). However, disease progression at 1 year appeared to favor GTR over STR (RR 0.66, 95% CI: 0.43-0.99, P<.001, NNT 26).
The authors pointed out that the results did not significantly change when studies that were 10 to 15 years old, classified as class III and class IV studies, and those with aggregate data were excluded.
Ultimately, the evidence was considered moderate to low based on the GRADE criteria.
“Based on 3 class II studies and many consistent class III studies, GTR probably increases the likelihood of 1-year survival compared with STR by about 61% and increases the likelihood of 2-year survival by about 19%,” the authors concluded.
Brown TJ, Brennan MC, LI M, et al. Association of the Extent of Resection With Survival in Glioblastoma: A Systematic Review and Meta-analysis. JAMA Oncol. doi:10.1001/jamaoncol.2016.1373.