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Richard S. Polin, Nicholas F. Marko, Matthew D. Ammerman, Mark E. Shaffrey, Wei Huang, Frederick A. Anderson Jr., Anthony J. Caputy and Edward R. Laws

Object. The goal of this study was to investigate survival and functional outcomes in patients with high-grade intracranial astrocytomas as a function of the location of the lesion in the dominant or nondominant hemisphere (DH and NDH, respectively), and to suggest management strategies for such patients based on these data.

Methods. Data were collected from the Glioma Outcomes Project database, a longitudinal database of demographic, clinical, and outcome data for patients with high-grade intracranial gliomas. From the entire database of 788 patients, a subset of all 280 right-handed patients with newly diagnosed, unilateral gliomas involving potentially eloquent cortex was selected as the sample population. Two cohorts were defined based on the location of the tumor in the right or left cerebral hemisphere. All other relevant demographic and clinical data were nearly identical between the cohorts. A Kaplan—Meier analysis was conducted to assess survival, and Karnofsky Performance Scale scores assigned at 6 and 12 months postoperatively were compared as a measure of functional outcome.

The analysis demonstrated no difference in survival between patients with lesions in the DH and those with tumors in the NDH. Additionally, no statistically significant difference in functional outcomes was observed between the two groups.

Conclusions. Laterality of high-grade gliomas is not an independent prognostic factor for predicting survival or functional outcome. The findings in this study demonstrate that fears of increased postoperative morbidity or mortality in otherwise resectable tumors of the DH are unfounded, and the authors therefore advocate that the surgeon's decision to operate be guided by validated outcome predictors and not biased by tumor lateralization.

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Nicholas F. Marko, Vivek A. Gonugunta, Amir H. Hamrahian, Ali Usmani, Marc R. Mayberg and Robert J. Weil

Object

Accurate assessment of the hypothalamic-pituitary-adrenal (HPA) axis is critical for appropriate management of the disease in patients with pituitary adenoma after transsphenoidal resection. The authors examine the role of the morning total serum cortisol level in the early postoperative period as a predictor of long-term HPA function.

Methods

Morning total serum cortisol was measured in 83 patients on postoperative Day 1 (or Day 2 if the patient received glucocorticoids during surgery) after transsphenoidal surgery for pituitary adenoma. These results were compared with those of definitive assays of HPA function performed at 1–3 months postoperatively, including cortrosyn/synacthen stimulation test (CST), insulin tolerance test (ITT), and metyrapone test (MTT). The ability of the early-postoperative morning cortisol level to predict HPA function was determined using standard confusion matrix calculations and receiver-operator control curve analysis.

Results

The authors found that an early postoperative morning total cortisol level ≥ 15 μg/dl is a sensitive and accurate predictor of normal HPA function in the postoperative period (sensitivity 80.5%, specificity 66.7%, positive predictive value 96.9%).

Conclusions

A morning total cortisol level ≥ 15 μg/dl in the early postoperative period after transsphenoidal surgery for pituitary adenomas is a good predictor of normal HPA function. This test has good sensitivity and accuracy and correlates well with the results of additional, definitive assays of HPA function (CST, ITT, and MTT) performed at 1–3 months postoperatively. Accordingly, it is the authors' practice to avoid exogenous perioperative glucocorticoid supplementation in patients with normal preoperative HPA function and postoperative morning total cortisol levels ≥ 15 μg/dl 1–2 days after transsphenoidal pituitary adenomectomy.

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Oral Presentations

2010 AANS Annual Meeting Philadelphia, Pennsylvania May 1–5, 2010

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Nicholas F. Marko and Robert J. Weil

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Nicholas F. Marko and Robert J. Weil

Considerable financial and human resources have been directed toward the emerging field of comparative effectiveness research (CER) in the US. Fundamentally, the concept of CER is so logical as to be almost self-evident; namely, that research regarding therapeutic strategies should go beyond efficacy and examine objectively their real-world effects and outcomes. In practice, however, reluctance to consider difficult questions related to the many dimensions of value in health care delivery and corresponding legislative constraints placed on the US CER enterprise risk limiting the ultimate utility of this investigative model. Significant constraints have been codified into the patient-centered outcomes research (PCOR) model of CER, which is emerging as the de facto method for conducting CER in the US. The experience of the authors as clinicians attempting to use CER to improve complex management decisions, for which multidimensional considerations of value represent a critical component of the overall effectiveness of alternate strategies, highlight the inability of PCOR to comprehensively inform this process. This suggests that PCOR may be a suboptimal approach for performing clinically relevant CER. In this editorial, the authors use clinical examples to highlight the limitations of the PCOR approach to CER and to propose an alternate approach, which they term “comparative, value-based effectiveness research” (CVER). The authors believe that the narrow scope and fundamental limitations of PCOR mitigate its overall value to medical decision-makers attempting to optimize overall effectiveness in the real-world setting, while a more comprehensive approach like CVER has greater potential to realize practical benefits for patients, clinicians, and society as a whole.

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Nicholas F. Marko, Emily LaSota, Amir H. Hamrahian and Robert J. Weil

Object

Acromegaly, a syndrome of excess growth hormone (GH) secretion typically caused by a GH-secreting pituitary adenoma, reduces life expectancy by approximately 10 years when left untreated. Treatment of acromegaly involves combinations of one or more discrete therapeutic modalities to achieve biochemical control. Unfortunately, data capable of informing decisions among alternate management strategies are presently lacking.

Methods

The authors performed a comparative effectiveness research (CER) review integrating efficacy, cost, and quality of life (QOL) analysis for treatment strategies comprising various combinations of surgery, radiotherapy, stereotactic radiosurgery, and pharmacotherapy in patients with acromegaly caused by a pituitary microadenoma. A management decision tree was used to identify 5 treatment strategies, each with up to 4 potential treatment steps. Efficacy was assessed using recent literature reports of biochemical control rates for each modality. Cost estimations were derived from wholesale drug prices and from the Healthcare Cost and Utility Project. Quality of life data were obtained from studies utilizing the Acromegaly Quality of Life Questionnaire.

Results

Individual treatment modalities were analyzed and ranked in each of 3 domains: highest rate of success, lowest cost, and highest QOL, and these scores were combined to facilitate comparison of overall effectiveness of each of the management strategies. These aggregate effectiveness scores were used to compare the 5 strategies from the decision tree, and a novel strategy was also proposed.

Conclusions

The choice of management strategy must be individualized for each patient with acromegaly. This CER analysis provides a comprehensive framework to inform clinical decisions among alternate management strategies in patients with GH-secreting pituitary microadenomas.

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Robert Michael Starke

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Alireza Mohammad Mohammadi, Pablo F. Recinos, Gene H. Barnett, Robert J. Weil, Michael A. Vogelbaum, Samuel T. Chao, John H. Suh, Nicholas F. Marko, Paul Elson, Gennady Neyman and Lilyana Angelov

Object

The authors evaluated overall survival and factors predicting outcome in patients with ≥ 5 brain metastases who were treated with Gamma Knife surgery (GKS).

Methods

Medical records from patients with ≥ 5 brain metastases treated with GKS between 1997 and 2010 at the Cleveland Clinic Gamma Knife Center were retrospectively reviewed. Patient demographics, tumor characteristics, treatment-related factors, and outcome data were evaluated.

Results

One hundred seventy patients were identified, with a median age of 58 years. The female/male ratio was 1.2:1. Gamma Knife surgery was used as an upfront treatment in 35% of patients and as salvage treatment in 65% of patients with multiple brain metastases. The median overall survival after GKS was 6.7 months (95% CI 5.5–8.1). At the time of GKS, 128 patients (75%) had concurrent extracranial metastases, and in 69 patients (41%) multiple extracranial sites were involved. Ninety-two patients (54%) had a history of whole-brain radiation therapy, and 158 patients (93%) had a Karnofsky Performance Scale (KPS) score ≥ 70. The median total intracranial disease volume was 3.2 cm3 (range 0.2–37.2 cm3). A total intracranial tumor volume ≥ 10 cm3 was observed in 32 patients (19%). Lower KPS score at the time of treatment (p < 0.0001), patient age > 60 years (p = 0.004), multiple extracranial metastases (p = 0.0001), and greater intracranial burden of disease (p = 0.03) were prognostic factors for poor outcome in the univariate and multivariate analyses.

Conclusions

In this study, GKS was safe and effective for upfront and salvage treatment in patients with ≥ 5 brain metastases. Gamma Knife surgery should be considered as an additional treatment modality for these patients, especially in the subset of patients with favorable prognostic factors.

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Nicholas F. Marko and Robert J. Weil

The WHO grading scheme for glial neoplasms assigns Grade II to 5 distinct tumors of astrocytic or oligodendroglial lineage: diffuse astrocytoma, oligodendroglioma, oligoastrocytoma, pleomorphic xanthoastrocytoma, and pilomyxoid astrocytoma. Although commonly referred to collectively as among the “low-grade gliomas,” these 5 tumors represent molecularly and clinically unique entities. Each is the subject of active basic research aimed at developing a more complete understanding of its molecular biology, and the pace of such research continues to accelerate. Additionally, because managing and predicting the course of these tumors has historically proven challenging, translational research regarding Grade II gliomas continues in the hopes of identifying novel molecular features that can better inform diagnostic, prognostic, and therapeutic strategies. Unfortunately, the basic and translational literature regarding the molecular biology of WHO Grade II gliomas remains nebulous. The authors' goal for this review was to present a comprehensive discussion of current knowledge regarding the molecular characteristics of these 5 WHO Grade II tumors on the chromosomal, genomic, and epigenomic levels. Additionally, they discuss the emerging evidence suggesting molecular differences between adult and pediatric Grade II gliomas. Finally, they present an overview of current strategies for using molecular data to classify low-grade gliomas into clinically relevant categories based on tumor biology.