on October 29th, 2014 No Comments
Last year, an estimated 70,000 people were diagnosed with a primary brain tumor, which originates and remains in the brain, and far more will develop metastatic brain tumors, those that begin as cancer elsewhere in the body and spread to the brain. Although physicians face a number of challenges in treating these tumors, the encouraging news is that advances in technology and new therapies are improving patient outcomes.
During a Stanford Health Library event on Thursday, Steven Chang, MD, director of the Stanford Neurogenetics Program and the Stanford Neuromolecular Innovation Program, will deliver an update on the latest in surgical and non-surgical treatments of brain tumors. (The lecture will also be webcasted for those unable to attend.) In anticipation of the talk, Chang answered some questions related to the topics he’ll be addressing.
Why has a greater understanding of genetics and the biology of tumors improved physicians’ understanding of how patients will respond to certain therapies?
Having a greater understanding of the genetics and biology of brain tumors helps neurosurgeons to tailor treatments for each patient. In essence, we are able to deliver personalized medicine if we understand which subsets of brain tumors respond to specific treatments. For example, we now understand that gliomas with certain genetic makers are more likely to respond to chemotherapy treatments. The presence or absence of these genetic markers will also help guide patients in determining which clinical trials it may be most appropriate for them to enroll in.
How have advances in brain-mapping technologies made a difference in treating low-grade gliomas, which are slow growing and often affect younger patients?
Low-grade gliomas don’t typically contrast enhance on brain MRI scans. Furthermore, low-grade gliomas are more likely than higher-grade gliomas to have appearances similar to normal brain tissue, with no obvious color or consistency distinction between tumor and normal brain. These factors make resection of low-grade gliomas potentially more complex than high-grade gliomas, which often have distinct appearances from normal brain tissue. Advances in brain-mapping technologies include both image guided navigation and electrophysiologic mapping. Image-guided navigation consists of the use of MR imaging to provide real-time guidance during tumor resections. High-speed computer workstations provide images that show neurosurgeons exactly where they are with respect to brain anatomy during tumor resections. Electrophysiologic mapping is the use of specific electrical simulations of the brain tissue to identify eloquent brain cortex. By mapping out these critical brain regions, the neurosurgeon can safely avoid them when performing tumor resection.
In what ways have improvements in imaging technology over the last decade changed the treatment approach for both surgical and non-surgical treatment of brain tumors?
Improvements in imaging technology over the last several years have provided valuable tools for neurosurgeons in the treatment of brain tumors. A significant advance in surgical treatment of brain tumors has been the development of intraoperative MRI scanners. This allows a surgeon to perform a tumor resection, and then, post resection, perform a set of MR imaging directly in the operating room. If this MR imaging shows residual tumor, the surgeon has an opportunity to perform a further resection prior to completing the surgical operation. Additional imaging advances include functional MR imaging. This provides a graphic representation of critical functions such as speech or motor function. This is useful in determining both whether a patient is inoperative candidate and in assessing risk of the surgical resection.