Impact of peri-tumoral resection on survival in primary glioblastoma

Glioblastoma (GBM) is the most common primary brain malignancy, and standard treatment includes maximal resection of contrast-enhancing tumor. Given recent interest in resection beyond areas of contrast-enhancement, the authors analyzed the role of peri-tumoral resection (PTR) in primary GBM.

This study included 126 adult patients with primary GBM amenable to peri-tumoral resection (PTR) at a tertiary care academic medical center. Patient characteristics and pre/postoperative tumor volumes were collected. Outcome-oriented cut-points for extent of resection of contrast-enhancing tumor (EOR) were determined using maximally selected rank statistics. Multivariable Cox proportional hazards (CPH) model for death was performed.

This cohort had mean age 60.7 ± 11.3 years and median overall survival (OS)/progression-free survival (PFS) 15.2/7.5 months. EOR >92.1% was associated with increased OS compared to <92.1% EOR (23.1 vs.14.0 months, p < .01). Fifty-four (42%) patients received PTR, of which 28 (22%) achieved PTR of >1.74 cm³ beyond the contrast-enhancing region. This latter group demonstrated greater OS than the PTR<1.74 cm³ group (21.6 vs. 16.8 months, p < 0.01). There was no significant difference in postoperative complications between groups. Multivariable CPH model found EOR 92.1%-99% (hazard ratio [HR], 0.30; confidence interval [CI], 0.15-0.60, p < .01) and PTR >1.74 cm³ (HR, 0.27; CI, 0.13-0.56, p < .01) were associated with increased OS. Preoperative T2-FLAIR volume >192 cm³ was associated with worse OS (HR, 3.18; CI, 1.17-8.61, p < .01).

Our results demonstrate increased OS in GBM with resection beyond contrast-enhancing tumor margins. With no associated increase in postoperative deficits, PTR >1.74 cm³ was both effective and safe in select cases.