In comparison, their counterparts -- 212 patients under 65 who had received the same therapies, but had more modest resections of the non-enhancing tumor -- survived only 16.5 months (1.4 years) on average, or about half as long. These results were verified with patient cohorts at the Mayo Clinic and the Cleveland Clinic's Ohio Brain Tumor Study.

Resecting Non-Enhancing Tumor Evens Survival Between Tumor Types

Among the group of longer-surviving patients, those with IDH-wild-type tumor did approximately as well as those with the IDH-mutant variant when a portion of the non-contrast enhancing tumor was removed, the authors noted. "The difference was that the patients with IDH-wild-type tumor declined more rapidly after the three-year mark," said first author Annette Molinaro, PhD, from the UCSF Department of Neurological Surgery, and the Department of Epidemiology and Biostatistics.

The researchers caution that maximal resection should only be achieved when it can be safely performed using techniques such as intraoperative brain mapping. This means that areas of the brain responsible for speech, motor, sensory and cognition are tested during surgery to ensure that these functional areas are preserved.

"There is a survival benefit for maximal resection for patients with glioblastoma, but as surgeons we must remove them in a manner that limits injury to the rest of the brain," said co-author and neurosurgeon Shawn Hervey-Jumper, MD, of the UCSF Brain Tumor Center and of the Weill Institute for Neurosciences.

Brain Mapping Is Critical for Aggressive Surgery

"Although these data show a survival benefit associated with maximal resection, it remains critically important that we do our best to remove tumor in a manner that will not harm the patient," Hervey-Jumper said, noting that about 80 percent of medical centers do not offer brain mapping.

While maximal resection of both enhancing and non-enhancing tumor should always be considered, Molinaro said that we are a long way from achieving a cure for glioblastoma.

"It's a complex tumor to treat for a number of reasons," she said. "One challenge is that the blood-brain barrier -- the network of blood vessels that acts as the brain's gatekeeper -- effectively blocks many cancer agents from reaching their target. Another challenge is that these are heterogenous tumors driven by multiple mutations -- if you target one mutation, others will thrive."


Co-Authors: There were 41 authors from seven institutions: UCSF; Oregon Health Sciences University, Portland; Emory University School of Medicine, Atlanta; Case Western Reserve University School of Medicine, Cleveland; Baylor College of Medicine, Houston; University Hospitals of Cleveland; Mayo Clinic Rochester, Minn. A full list of authors, funding and disclosures can be found in the published article.

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