Robert J. Weil
Nicholas F. Marko and Robert J. Weil
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.
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.
Rina G. Khatri, Kapila Navaratne and Robert J. Weil
Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults, with a 5-year survival rate of < 5%. Aberrant function of TP53 is common in GBM. Although mutational inactivation of p53 is found in many cases, there remain tumors in which genetic alterations of p53 are absent. Negative regulators of the TP53 pathway such as MDM2, which directly inhibits TP53 expression and activity, may influence the pathogenesis of GBM. To understand its potential function in gliomagenesis, the authors analyzed a novel single nucleotide polymorphism (SNP) in the MDM2 promoter that enhances MDM2 expression.
The investigators isolated DNA from 98 patients with GBM and 102 healthy, cancer-free controls. A polymerase chain reaction analysis was performed to determine the MDM2 SNP309 genotype by using distinct primer pairs for the wild-type (T) and mutant (G) alleles.
The frequency of the mutant MDM2 polymorphism was found to be higher (p = 0.0092) in patients with GBM (54.6%) compared with healthy controls (41.2%); the TT and GG genotypes were more common in healthy controls and patients with GBM (p = 0.0004 and p = 0.02, respectively). Although there was no association between the MDM2 SNP309 and overall survival, the GG genotype was associated with development of GBM at a younger age in patients with tumors harboring wild-type p53, which may mitigate the effect of the MDM2 SNP.
Although the MDM2 SNP309 does not portend decreased survival, the increased incidence of the mutant G allele in patients with GBM and its influence on age of onset suggest a potential role in the molecular pathogenesis of GBM, and may be a therapeutic target.
Russell R. Lonser, Ronald R. Buggage and Robert J. Weil
Kim J. Burchiel
Robert Michael Starke
Nicholas F. Marko, Emily LaSota, Amir H. Hamrahian and Robert J. Weil
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.
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.
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.
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.
Michael L. Kelly, Daniel P. Sulmasy and Robert J. Weil
Decision making for patients with spontaneous intracerebral hemorrhage (ICH) poses several challenges. Outcomes in this patient population are generally poor, prognostication is often uncertain, and treatment strategies offer limited benefits. Studies demonstrate variability in the type and intensity of treatment offered, which is attributed to clinical uncertainty and habits of training. Research has focused on new techniques and more stringent evidence-based selection criteria to improve outcomes and produce consensus around treatment strategies for patients with ICH. Such focus, however, offers little description of how ICH treatment decisions are made and how such decisions reflect patient preferences regarding medical care. A growing body of literature suggests that the process of decision making in ICH is laden with bias, value assumptions, and subjective impressions. Factors such as geography, cognitive biases, patient perceptions, and physician characteristics can all shape decision making and the selection of treatment. Such factors often serve as a barrier to providing patient-centered medical care. In this article, the authors review how surgical decision making for patients with ICH is shaped by these decisional factors and suggest future research pathways to study decision making in ICH. Such research efforts are important for establishing quality guidelines and pay-for-performance measures that reflect the preferences of individual patients and the contextual nature of medical decision making.