Researchers have found that preoperative stereotactic radiosurgery is associated with low rates of tumor recurrence, adverse radiation effects, and meningeal disease in patients with metastatic brain tumors, according to a novel study published by Prabhu et al in JAMA Oncology.
Background
As metastatic brain tumors grow, they can cause symptoms such as headaches, seizures, weakness, or balance issues. For some patients who have a limited number of tumors, surgery and stereotactic radiosurgery can help alleviate these symptoms.
Brain metastases can also result in meningeal disease—which occurs when the cancer spreads to nearby fluid and can grow on the surface of the brain.
Despite what its name implies, stereotactic radiosurgery isn’t actually a type of surgery, but instead involves highly focused radiation that targets tumors while minimizing the effects on surrounding healthy tissue. The treatment is often used after patients undergo surgical resection of their brain tumors—postoperative stereotactic radiosurgery—however, the therapy can also be given before surgery in a process called preoperative stereotactic radiosurgery.
“Postoperative [stereotactic radiosurgery] is currently the standard of care in these patients, but there is a growing body of research that shows preoperative [stereotactic radiosurgery] has advantages,” explained lead study author Roshan Prabhu, MD, MS, Adjunct Associate Professor of Radiation Oncology, Medical Director of Radiation Oncology at the Levine Cancer Institute, and Director of Radiation Oncology Research at Atrium Health.
According to research from a previous study—published by Patel et al in Neurosurgery—there are multiple reasons why the preoperative procedure may benefit patients more than the postoperative procedure. In preoperative stereotactic radiosurgery, the tumor is intact, so physicians can more precisely see the area that needs treatment.
“We’ve … conducted research that shows there’s a higher risk of tumor cells spreading to the fluid around the brain when surgery occurs first,” Dr. Prabhu noted. “Preoperative [stereotactic radiosurgery] can help minimize that risk,” he highlighted.
Study Methods and Results
In the new study, researchers examined the cases of 404 patients who underwent preoperative stereotactic radiosurgery and surgical resection of their brain metastases.
To analyze preoperative outcomes, the researchers then looked at cavity local recurrence; meningeal disease; and adverse radiation effects such as swelling, inflammation, and radiation necrosis—which can result in long-term swelling as a result of minimal blood supply to tissues.
After 2 years of follow-up, the researchers found that the rate of cavity local recurrence was 13.7%, the rate of meningeal disease was 5.8%, and the rate of symptomatic adverse radiation effects was 5% in patients who underwent preoperative stereotactic radiosurgery.
While this study did not directly compare outcomes with patients treated with postoperative stereotactic radiosurgery, recent studies have shown that the postoperative procedure cavity recurrence rates, meningeal disease rates, and adverse radiation effects rates tend to be 22% to 39%, 16% to 21%, and 7% to 18%, respectively.
Additionally, the researchers revealed that the novel risk factors for these outcomes following treatment with preoperative stereotactic radiosurgery included extent of resection, tumor type, number of preoperative procedure fractions used, and the type of surgery.
Conclusions
“We found negative outcomes to be notably low with preoperative [stereotactic radiosurgery], especially when compared to what is expected after [the] postoperative [procedure],” Dr. Prabhu underscored. “By simply changing the sequencing of treatment, it can potentially improve outcomes and increase survival,” he concluded.
The new findings served as the basis for a national phase III randomized clinical trial—currently enrolling patients at multiple sites—designed to compare preoperative stereotactic radiosurgery to postoperative stereotactic radiosurgery.
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.
