In reading a recent article in the journal Progress in Neurological Surgery by Monaco et al., I started thinking about the ways in which treating brain metastases has shifted over the past 20 years. As the article explains, back then, a person diagnosed with brain metastases was treated palliatively—the goal of which was to relieve discomfort during the final stages of life. As treatment evolved, whole-brain radiation therapy became a mainstay. It helped increase survival time and was also thought to help prevent future metastases. Surgery was available, but only for a very small number of people—a person had to be otherwise healthy with a single tumor in an operable location. A combination of surgery—when possible—and whole-brain radiation offered the best results.
As advances in chemotherapy have come to the forefront, patients with metastatic cancer are surviving longer. As a result, we’re now beginning to see some of the long-term side effects of whole-brain radiation therapy. These can include progressive changes in learning, memory loss, speech problems and personality changes.
As the name implies, whole-brain radiation treats the entire brain. In one way, that’s a good thing: It not only treats the targeted tumor, but also microscopic tumors that are too small to see with modern brain imaging. However, the flip side of that coin means that healthy tissue also receives radiation. While the visible tumors can be controlled, one’s quality of life may be significantly injured due to radiation changes that occur in the regions of the brain responsible for memory, learning and speech.
At The Gamma Knife Center at The Valley Hospital, our treatment paradigm is designed to control all visible brain tumors while sparing critical areas of the brain that aren’t affected by cancer. The Gamma Knife Perfexion, the latest Gamma Knife model, makes this vision an everyday reality. The Gamma Knife Perfexion performs stereotactic radiosurgery in a single treatment session that requires no hospital stay. Furthermore, recent data suggests that patients treated with stereotactic radiosurgery alone improves survival in patients suffering from metastatic brain cancer. Researchers theorize that this survival benefit may be a result of the ability to continue systemic chemotherapy during stereotactic radiosurgery as opposed to suspending chemotherapy (which is necessary during whole brain radiation therapy).
With the Perfexion, multiple metastases can be treated quickly during the same treatment session. With the advanced imaging available today, recent studies have shown no difference in survival between people treated with stereotactic radiosurgery together with whole-brain radiation and stereotactic radiosurgery alone. In fact, some experts believe that stereotactic radiosurgery followed by imaging surveillance to identify tumor progression or new metastases and retreatment with radiosurgery may be the best way to treat patients effectively while maintaining brain function and quality of life. As the authors conclude, “Although [whole brain radiation] may marginally improve local tumor control and provide some protection against the development of new brain metastases, it does so at a significant toxicity risk. We believe that [repeat stereotactic radiosurgery] can effectively manage both local tumor progression and new brain metastases and avoid unnecessary global brain injury.”