When Brain Cancer Returns, Test May Aid Decisions about Surgery
Neurosurgeons who regularly operate on patients with malignant brain tumors learn to identify which patients are good candidates for additional surgeries when the disease recurs, as it usually does. And while there is no substitute for a surgeon’s experience, a new test could help select patients who may benefit from surgery to treat recurrent glioblastoma multiforme (GBM), the most common brain tumor in adults.
The test uses readily available preoperative clinical information to quantify the likelihood of survival after surgery. Predictions are based on a scale of three factors associated with prognosis—how well a patient performs day-to-day tasks, the volume of a tumor, and whether the tumor is in or near critical regions of the brain.
“We think the scale could help patients and families decide whether to have surgery,” said Dr. John Park of the National Institute of Neurological Disorders and Stroke, who led the team that developed the scale. In a retrospective study of 34 patients with recurrent GBM, those who scored lowest on the scale lived longer than those with higher scores, a statistically significant finding that was validated in a second population of patients.
In addition to aiding decisions about surgery, the scale may be helpful for stratifying patients during enrollment in clinical trials, the researchers said online July 19 in the Journal of Clinical Oncology.
“This study is a significant contribution to the scientific literature,” said Dr. John Yu, director of the Brain Tumor Center at Cedars-Sinai Medical Center, who was not involved in the research. “Those of us who do a lot of these surgeries have an intuitive sense of how patients will do. Dr. Park took what we intuitively know and formalized it into a simple scale for determining whether a patient is a viable candidate for surgery.”
Seeing a Benefit
The test, called the NIH Recurrent GBM Scale, gives patients a total score of 0 to 3 points. After surgery, patients with 0 points had relatively good survival (10.8 months), while those with 1 to 2 points had intermediate survival (about 4.4 months) and those with 3 points had poor survival (1 month).
For the group that fared the best, the median overall survival was 24.9 months, including the time from diagnosis to additional surgeries. The median overall survival for all patients with GBM is approximately 14 months. “The results of this study suggest that a lot of patients do benefit from additional surgery,” despite the risks, said Dr. Park.
The study was not designed to assess the role of postoperative therapies such as radiation and chemotherapy in the survival of patients, noted Dr. Yu. But he acknowledged that, for many patients, the available treatments are not effective. “We need novel therapies for this disease,” he said.
Dr. Park agreed with this point and said that patients with good prognostic scores should be encouraged to have surgery and then to join an appropriate clinical trial of an experimental treatment.
In the validation component of the study, the researchers applied the scale to 109 patients treated at Brigham and Women’s Hospital. As with the NIH patients, there were statistically significant differences in the postoperative median survival between groups with the lowest and highest scores.
“The value of this scale is that it gives you a good sense of which patients should not be sent to surgery, because their survival is likely to be so short that they would not see a benefit,” said Dr. Howard Fine, chief of the Neuro-Oncology Branch in NCI's Center for Cancer Research and a senior author of the study. “If we could save patients from surgery who ultimately would not benefit from it, then we’ve done a service.”
Developing genetic and other kinds of molecular markers for assessing the prognosis of patients is an active area of research in the field. “As our knowledge of the genetics involved in tumors increases, we’ll have to add clinical information from the patient with genetic parameters to refine prognostication,” said Dr. Yu. “But the decision to do surgery may be influenced more by clinical parameters.”
Furthermore, it’s not yet clear whether the results from this study will be applicable to surgeons in smaller community hospitals who do very few such surgeries each year, noted Dr. Yu. The study should therefore be validated in the community setting as well as additional large medical centers, he said.
As new therapies are introduced, the scale may need to be updated or revised. In the future, Dr. Fine explained, new treatments could make surgery worthwhile for patients who are currently in the worst-prognosis group and who, based on today’s treatment options, would be unlikely to realize a benefit from surgery.
“This is a very important study relative to the care of gliomas now,” he continued. “Here at the NIH, we’re generally geared toward the future and new treatments, but the power of this study is that it should help us improve the care of patients today.”
—Edward R. Winstead