AANS Neurosurgeon | Volume 28, Number 3, 2019


The Science of Practice – Neurosurgical Oncology

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As U.S. health care spending continues to increase, Americans are paying more attention to the cost, safety and quality of the care provided. As neurosurgeons, we should play a leadership role in pushing for precise measurement of the value of the care delivered and providing high-quality information about the therapeutic- and cost-effectiveness of the medical and surgical interventions used in our discipline. Clearly, this is a moving target, as science and technology change. This is clearly true for the science of practice in the neurosurgical oncology subspecialty, which we explore in terms of the past, present and future.

The Past

Historically, a small percentage of neurosurgeons have produced most of the knowledge in neurosurgical oncology. Prominent surgeons published a personal series based on personal records. Dr. William Osler himself advocated for grouping one’s own cases into three categories of “clear”, “doubtful” and “mistakes” cases to gain wisdom with experience. Dr. Harvey Cushing, with the help of his skilled pathologist, Dr. Louise Eisenhardt, published his own early series of brain tumor cases, many of which involved using finger dissection of the tumor. Not surprisingly, this maneuver often resulted in significant hemorrhage and poor outcome. For the majority of the 20th century, the single surgeon series has been the norm and was often pivotal in pushing the field forward. For example, Dr. M. Gazi Yasargil’s experience with 4,200 microneurosurgeries and Dr. Madjid Samii’s reported series of 1,000 vestibular schwannomas garnered widespread recognition in an era when other types of published data that were of similar sample size were not readily available.

The Present

This is an exciting era of neurosurgery, with an explosion of scientific studies affecting and improving neurosurgical oncology practice. Over the last few decades, retrospective analyses of institutional data became more popular, along with institutional and perhaps multi-institutional prospective studies (including randomized clinical trials) to compare outcome and cost-effectiveness of interventions. Also, there are currently several prospective studies focused on quality of life or neurological function as measurable clinical outcomes. These examine the effect of surgery and/or adjuvant therapies delivered perioperatively on the preservation or improvement of neurological function.

Concurrently, our specialty began to build national databases to measure clinical outcomes retrospectively. Within the last decade, the spine neurosurgeons helped to establish the National Neurosurgery Quality and Outcomes Database, now known as Quality Outcomes Database (QOD), to ultimately improve the quality of care, allow for more efficient allocation of health care resources and advance the science of neurosurgical care. Nationally, the SEER and NCDB databases have collected clinical information on all cancer patients, including neuro-oncology patients. Though we currently have the Central Brain Tumor Registry of the United States, which provides population-based epidemiological data, we have yet to build a large-scale national clinical database containing neurological outcome specifically designed for neurosurgical oncology to allow for scientific inquiry aimed at improving every aspect of care.

The Future

The age of big data has already arrived. As we look to the future, a significant advancement in neurosurgical oncology will be the practice of precision medicine. Instead of providing treatments designed for the “average patient,” neurosurgeons will be able to provide personalized, precision medicine based on an individual patient’s unique symptoms, tumor biology and background genetics. This is in accordance with the broader trend in medicine where 42 percent of all new drug approvals by the FDA were personalized medicine treatments. Many are targeted cancer therapies based on specific biomarkers or mutations. 

The personalization aspect of precision medicine begins with precisely characterizing the patient. The FDA is already beginning to establish regulatory oversight in anticipation of the wave of next generation sequencing (NSG) tests that are becoming available for clinical and research purposes. Clinically, NSG tools for genomic profiling of each patient and tumor that have been recently developed by Foundation Medicine will become more widely used to help match patients with approved targeted therapies, immunotherapies and clinical trials. Additional examples of genomic-based clinical laboratory services include Genomic Health and Myriad Genetics. Other precision medicine tools, such as those developed by Tempus, Flatiron Health and Syapse, allow for additional integration of genomic and personalized clinical data with the existing electronic medical record infrastructure.

On the research and scientific side of neurosurgical oncology, the cBioPortal and CBTTC are two large molecular databases that collect and disseminate biological data on adult and pediatric tumors amongst researchers. We believe these excellent platforms for collecting and sharing valuable data across institutions will fast track bench-to-bedside innovations. However, they can also be made better. Future versions should allow better integration of relevant clinical neurosurgical data into the existing infrastructure of tumor molecular data to ultimately allow for multi-dimensional analyses of different aspects of neuro-oncological care as they impact a variety of outcome measures for our patients. Given that many leading neurosurgical institutions already maintain their own clinical and molecular databases, our subspecialty should integrate all relevant patient clinical and biological data from various institutions into an easily accessible, unified platform.


The science of neurosurgical oncology practice has evolved over the last two centuries. As more clinical and biological data are systematically generated, we are ushering in a new age of precision medicine in our field that will allow us to deliver customized treatment for the right patient at the right time. We should also strive to create better data infrastructures, along with proper incentives for universal buy-in from all stakeholders (i.e., providers, patients and payors), so that we will have more informative data in order to generate the scientific discoveries that will lead to the innovations in neurosurgical oncology practice in the future.  

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Angela Waterford | August 27, 2019 at 6:53 pm

Wow, I didn’t know that neurological surgical breakthroughs can now provide my mother with precision medicine to treat her tumor. I think she should visit a specialist first so that she’ll know how much these procedures will cost. If this will save her life, I’m willing to take her to one.