Image-Guided Hypofractionated Stereotactic Radiosurgery: A Practical Approach to Guide Treatment of Brain and Spine Tumors PDF

Preface

There is no doubt that single-fraction brain radiosurgery has transformed the management of brain metastases. Patients are no longer reflexively treated with whole brain radiation therapy, and it has been recently proven that radiosurgery alone enables many patients to maximize both quality of life and neurocognitive function. At the time of its development, brain radiosurgery was limited to a few sites and technologies, and required an invasive head frame. With improvements and increasing radiosurgery demand, the technology has evolved such that we can deliver radiosurgery within both academic and community practices. Technological advances such as image guidance, micro-multileaf collimators, intensity-modulated radiotherapy, robotic technology, and frameless stereotaxy are quickly becoming standard features on modern linear accelerators, thereby enabling patient access to what is now considered a standard practice for patients with limited brain metastases.

In this book, we provide detailed chapters on the technology, as it is imperative that we understand the capabilities of the technology to maximize efficacy. One such advance is to hypofractionate brain metastases. It has been shown that local control decreases with increasing tumor volume and, by taking advantage of a few fraction approaches, we can dose escalate while maintaining acceptable risks of radiation necrosis. We provide detailed chapters specific to the rationale and clinical outcomes with hypofractionated brain metastases, benign brain tumors, gliomas, and surgical metastases cavities. This trend to hypofractionate will fast become a standard approach, and we are only at the beginning of a transformative phase in the optimization of radiosurgical management of brain tumors.

With radiosurgery having a firm role in the brain, and advances in technology permitting high-precision conformal radiation to body sites, it was only natural for the field to develop stereotactic body radiotherapy (SBRT). One of its applications was in the spine. Similar to the brain, the idea was to maximize local tumor control and pain control, and prevent neurologic catastrophes (malignant epidural spinal cord compression). SBRT has been applied to intact spinal metastases, previously radiated metastases and, increasingly, residual tumors in the postoperative patient. In fact, the trajectory is similar to that of brain indications such that benign spinal tumors are also treated with spine SBRT. What is distinct from the evolution of brain radiosurgery is the ability at the forefront to deliver radiation in a hypofractionated approach rather than just a single-fraction one. There are advantages and disadvantages to either approach, and we provide chapters on the rationale and clinical experience with both fractionation schemes specific to spinal tumors. We have learned a tremendous amount in the last five years, and the current work includes expert perspectives that summarize contemporary philosophies on SBRT and hypofractionation.

We also have a dedicated chapter focused on the vascular effect with hypofractionation, as we have increasingly learned that these pathways may explain the often dramatic responses seldom seen with low-dose standard fractionation schemes. Last, as imaging is crucial to our field, we have a dedicated chapter to advanced magnetic resonance (MR) imaging of the brain, and we expect in the future that spinal imaging will advance as well with functional applications.

It is our honor to provide readers with this compilation specific to brain and spinal indications with hypofractionation, and we include a checklist with each clinical chapter for implementing these approaches into your practices.