Fixed and Variable Factors that Impact a Brain Tumor Patient’s Prognosis
A Q&A with Burt Nabors, MD, Professor and Director of the Division of Neuro-oncology at the University of Alabama, Birmingham, and a member of the Cancer Commons Brain Tumor Advisory Board; firstname.lastname@example.org
Q: Primary brain gliomas can be devastating, often deadly, malignancies. Obvious prognostic factors include whether they are grade 1, 2, 3, or 4; their extent of growth prior to diagnosis (stage); and their location, such as in the brain stem. What are other key factors that affect prognosis? Some say that the skill of the original surgeon is the most important prognostic factor. Others suggest that the size (case volume) of the initial treating institution is most important. What do you think?
A: An excellent question and one I may try to answer in two ways. The first are the known and well-quantified prognostic factors. The two most powerful are the patient’s age and their performance status. Age is a pretty clear factor and one we cannot alter. We in the neuro-oncology community are seeing increased attention to treatment recommendations based on age, both at the young and older ends of the spectrum. These efforts do appear to provide brain tumor patients in those spaces improved outcomes. However, as a modifiable prognostic factor, age is not one.
A patient’s performance status is, at the core, a measure of how well they retain their station in life and can manage their activities of daily living independently. It most likely reflects the summation of several other factors, such as the location of the tumor, the grade, and the ability of the neurosurgeon to safely resect (remove) tumor. When looking simply at tumor location, we do see improved outcomes for tumors in the non-dominant hemisphere or in more silent regions, such as the frontal or anterior temporal lobes compared to more eloquent or vulnerable brain regions. However, again, the location of the tumor is not modifiable by the individual patient. It is where it is.
As you suggest, another—and modifiable—way to consider this question is to focus on the experience and skill of the neurosurgeon. I would submit the factors that have the greatest impact here are the training environment for the neurosurgeon, the experience and interest of the neurosurgeon in brain cancer, and the volume of the treatment facility. Surgery at centers involved in high volumes of brain tumor surgery with neurosurgeons who are dedicated to advancing the practice of surgical intervention is an important consideration.
The current practice of the neurosurgeon also has a significant impact on patient outcomes. This has been well quantified and published, clearly for high-grade glial tumors such as glioblastoma, but also for lower-grade tumors such as astrocytoma and oligodendroglioma WHO II. This need for a dedicated practice is typically seen in environments that offer pre-operative neurological function mapping, advanced imaging modalities, and intraoperative awake craniotomy with cortical mapping. When this degree of neurosurgical sophistication is available, it is often in settings with multidisciplinary groups, including a research base with an intense interest and focus on brain cancers.
An unfortunate current reality is that, most often, settings with this degree of sophistication are in our larger urban centers, where ease of access for patients living and presenting in a more rural environment can be quite a challenge. Creating opportunities to provide access and equal care to all remains a significant part of the neuro-oncology mission and challenge.
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