Glioblastoma is an aggressive primary brain tumor with devastatingly poor prognosis. Multiple studies have shown the benefit of wider extent of resection (EOR) on patient overall survival (OS) and worsened survival with larger preoperative tumor volumes. However, the concomitant impact of postoperative tumor volume and eloquent location on OS has yet to be fully evaluated. We performed a retrospective chart review of adult patients treated for glioblastoma from January 2006 through December 2011. Adherence to standardized postoperative chemoradiation protocols was used as an inclusion criterion. Detailed volumetric and location analysis was performed on immediate preoperative and immediate postoperative magnetic resonance imaging. Cox proportional hazard modeling approach was employed to explore the modifying effects of EOR and eloquent location after adjusting for various confounders and associated characteristics, such as preoperative tumor volume and demographics. Of the 471 screened patients, 141 were excluded because they did not meet all inclusion criteria. The mean (±SD) age of the remaining 330 patients (60.6% male) was 58.9 ± 12.9 years; the mean preoperative and postoperative Karnofsky performance scores (KPSs) were 76.2 ± 10.3 and 80.0 ± 16.6, respectively. Preoperative tumor volume averaged 33.2 ± 29.0 ml, postoperative residual was 4.0 ± 8.1 ml, and average EOR was 88.6 ± 17.6%. The observed average follow-up was 17.6 ± 15.7 months, and mean OS was 16.7 ± 14.4 months. Survival analysis showed significantly shorter survival for patients with lesions in periventricular (16.8 ± 1.7 vs. 21.5 ± 1.4 mo, p = 0.03), deep nuclei/basal ganglia (11.6 ± 1.7 vs. 20.6 ± 1.2, p = 0.002), and multifocal (12.0 ± 1.4 vs. 21.3 ± 1.3 months, p = 0.0001) locations, but no significant influence on survival was seen for eloquent cortex sites (p = 0.14, range 0.07-0.9 for all individual locations). OS significantly improved with EOR in univariate analysis, averaging 22.3, 19.7, and 13.2 months for >90, 80-90, and 70-80% resection, respectively. Survival was 22.8, 19.0, and 12.7 months for 0, 0-5, and 5-10 ml postoperative residual, respectively. A hazard model showed that larger preoperative tumor volume [hazard ratio (HR) 1.05, 95% CI 1.02-1.07], greater age (HR 1.02, 95% CI 1.01-1.03), multifocality (HR 1.44, 95% CI 1.01-2.04), and deep nuclei/basal ganglia (HR 2.05, CI 1.27-3.3) were the most predictive of poor survival after adjusting for KPS and tumor location. There was a negligible but significant interaction between EOR and preoperative tumor volume (HR 0.9995, 95% CI 0.9993-0.9998), but EOR alone did not correlate with OS after adjusting for other factors. The interaction between EOR and preoperative tumor volume represented tumor volume removed during surgery. In conclusion, EOR alone was not an important predictor of outcome during GBM treatment once preoperative tumor volume, age, and deep nuclei/basal ganglia location were factored. Instead, the interaction between EOR and preoperative volume, representing redu...

abbreviatioNs CSF = cerebrospinal fluid; EOR = extent of tumor resection; GTR = gross-total resection; QOL = quality of life; STR = subtotal resection; TNTS = transnasal transsphenoidal. obJective The comparative efficacy of microscopic and fully endoscopic transsphenoidal surgery for pituitary adenomas has not been well studied despite the adoption of fully endoscopic surgery by many pituitary centers. The influence of surgeon experience has also not been examined in this setting. The authors therefore compared the extent of tumor resection (EOR) and the endocrine outcomes of 1 very experienced surgeon performing a microscopic transsphenoidal surgery technique with those of a less experienced surgeon using a fully endoscopic transsphenoidal surgery technique for resection of nonfunctioning pituitary adenomas in a concurrent series of patients. methods Post hoc analysis was conducted of a cohort of adult patients prospectively enrolled in a pituitary adenoma quality-of-life study between October 2011 and June 2014. Patients were followed up for 6 months after surgery. Patients were treated either by a less experienced surgeon (100 independent cases) who practices fully endoscopic surgery exclusively or by a very experienced surgeon (1800 independent cases) who practices microscopic surgery exclusively. Patient demographic characteristics, tumor characteristics, hypopituitarism, complications, and length of hospital stay were analyzed. Tumor volumes and EOR were determined by formal volumetric analysis involving manual segmentation of MR images performed before surgery and within 6 months after surgery. Logistic regression analysis was used to determine predictors of EOR. results Fifty-five patients underwent fully endoscopic transsphenoidal surgery, and 80 patients underwent fully microscopic transsphenoidal surgery. The baseline characteristics of the 2 treatment groups were well matched. EOR was similar between the endoscopic and microscopic groups, respectively, as estimated by gross-total resection rate (78.2% vs 81.3%, p = 0.67), percentage of tumor resected (99.2% vs 98.7%, p = 0.42), and volume of residual tumor (0.12 cm 3 vs 0.20 cm 3 , p = 0.41). Multivariate modeling suggested that preoperative tumor volume was the most important predictor of EOR (p = 0.001). No difference was found in the development of anterior gland dysfunction (p > 0.14), but there was a higher incidence of permanent posterior gland dysfunction in the microscopic group (p = 0.04). Combined rates of major complications and unplanned readmissions were lower in the endoscopic group (p = 0.02), but individual complications were not significantly different. coNclusioNs A less experienced surgeon using a fully endoscopic technique was able to achieve outcomes similar to those of a very experienced surgeon using a microscopic technique in a cohort of patients with nonfunctioning tumors smaller than 60 cm 3 . The study raises the provocative notion that certain advantages afforded by the fully endoscopic technique may impact the learning c...

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