Predicting Outcomes After Glioma Surgery: Model Behavior

Abstract

The ability to predict outcomes for individual patients undergoing craniotomy for resection of gliomas would be of great value to physicians, patients, families, and thirdparty payers. For instance, having precise knowledge of the personal potential for complications as well as the relative frequency of these unanticipated outcomes could help prepare patients and their loved ones for appropriate postoperative recovery. At present, of course, this is not a reality; however, neurosurgical oncologists are well versed in using molecular biomarkers such as isodehydrogenase-1 or methylguanine methyltransferase methylation status as well as histologic grade to help predict patient overall survival. They also have convincing evidence of the influence of their surgical efforts and patient demographics on overall survival. It is understood that overall survival and progression-free survival can be predicted by age, preoperative Karnofsky Performance Score, and extent of resection (8, 12). Nevertheless, it has not been possible to provide a patient with an individualized expectation of risk for postoperative complications. In a paper recently published in WORLD NEUROSURGERY, Missios et al. have attempted the task of determining preoperative predictive indicators of potential postoperative complications for patients undergoing craniotomy for glioma resection. They have a track record of doing similar analysis for other intracranial tumors: In a study similar to this, they described a predictive model of unfavorable outcomes for patients undergoing resection of benign intracranial tumors (2). Using multivariate analysis of a national database, they identified the effect of various risk factors on the incidence of death (1.3%), unfavorable discharge (22.7%), hydrocephalus (4.2%), cardiac (1.1%) or respiratory (0.9%) complications, deep venous thrombosis (DVT) (0.5%), pulmonary embolus (2.3%), and acute renal failure (1.5%). In their article in this month’s issue, they evaluated the records of over 20,000 patients with glioma included in a national database who underwent craniotomy and identified similar inpatient postoperative risks, including a 1.6% risk of mortality, and morbidity risk of 25.8% for discharge to rehabilitation, 4.0% for treated hydrocephalus, 0.7% for cardiac complications, 0.5% for respiratory complications, 0.8% for deep wound infection, 0.6% for DVT, 3.1% for pulmonary embolus, and 1.3% for acute renal failure. These numbers proved to be very similar for benign and malignant intracranial disease. Mortality is almost identical in both studies, as is true of most of the other postoperative complications. Discharge to rehabilitation is slightly higher for the glioma group but the difference is small and it is unclear whether it would be of statistical significance.