المتخصصون في المجالات الطبية

Oct. 01, 2026

Decision-making about brain tumors is fraught with ambiguity. Are signs of recurrence on post-treatment imaging true recurrence or pseudo-progression? What can be done if standard therapy seems unlikely to help? Mayo Clinic has teams of experts who pool their knowledge and can recommend cutting-edge, personalized approaches.

"We have multidisciplinary tumor boards to collaboratively think through an individual case, work through decision trees of potential options and come to a group consensus of recommendations," says Terry C. Burns, M.D., Ph.D., a neurosurgeon at the Mayo Clinic Comprehensive Cancer Center in Rochester, Minnesota. "There may not be a clear path forward. But we can tailor an approach for the patient."

Mayo Clinic uses advanced imaging and testing, including methylation testing, for precise diagnosis of primary, recurrent and metastatic tumors. Patients might be eligible for clinical trials of new therapies at Mayo Clinic or other centers.

Personalized care can involve early evaluation of patients to identify the best possible tumor biomarkers. "We are increasingly designing biomarkers tailored uniquely to patients," Dr. Burns says. "If part of the tumor shows an amplification, we may be able to use whole-genome sequencing to develop individualized primers for that single patient. It's time-consuming, so we don't want to be up against the wall when we start the process."

Early evaluation also helps ensure that a patient's plasma or cerebrospinal fluid (CSF) is banked from multiple time points. "That allows testing to accurately reflect changes in disease burden resulting from surgery and initial treatment," Dr. Burns says. "It's leveraging a research toolkit to help improve patient care."

Diagnosis of tumor recurrence

Mayo Clinic's brain tumor boards bring together specialists in neuro-oncology, neurosurgery, neuroradiology, pathology and radiation oncology. "With sometimes dozens of healthcare professionals and experts on these boards, we benefit from diverse insights that can yield an out-of-the-box strategy to best meet a patient's unique needs," Dr. Burns says. "The wisdom of the crowd is important to making the best recommendations in some of the most difficult situations."

Accurately differentiating tumor progression from pseudo-progression is one major challenge. Mayo Clinic has long been a developer and user of 18F-DOPA positron emission tomography (PET) for tumor detection. Patients also might benefit from new and potentially improved PET tracers, including 18F-FET — which is under investigation for U.S. Food and Drug Administration approval — or off-label use of fluciclovine PET.

CSF analysis is another option. Multiple companies are developing tests for tumor-derived DNA in biofluids.

"Patients with tumor-derived cell-free DNA detectable in CSF are more likely to be experiencing a true recurrence. But the even stronger predictor is directionality," Dr. Burns says. "If cell-free DNA is present but not changing, we need to keep an eye on things. But we're not in dire straits. However, an increasing abundance of tumor-derived cell-free DNA alerts us of the urgent need to pivot to an alternate strategy for that patient, if possible."

Although biomarker trajectories are likely to become mainstream, biopsy is still the gold standard for confirming tumor recurrence. "At Mayo Clinic, we have a relatively low threshold to biopsy if it's safe and clinically appropriate," Dr. Burns says.

He notes the importance of interpreting biopsy results in context. "We're increasingly appreciating that there are limitations to results from a single snapshot in time," Dr. Burns says. "Unfortunately, sooner or later, the tumor is going to come back. We've had cases when we perform a biopsy and don't see much, but the mass continues to grow and we then end up removing what turns out to be glioma. There can be an evolving combination of treatment-induced changes and tumor recurrence. The trajectory of biomarkers and amino acid PET imaging can add important context."

Complex, patient-centered decisions

Analyzing tumor DNA is another important tool for planning care. As a major quaternary center, Mayo Clinic offers methylation testing to classify tumor types, predict prognosis and guide targeted therapies.

"Certain tumors can look reasonably well-behaved under the microscope, lacking various chromosomal alterations. But then the methylation testing alerts us that the tumor may be much more aggressive than expected," Dr. Burns says. "We sometimes have borderline cases. For example, some grade 3 IDH-mutant astrocytomas behave more like grade 2. Others behave more like grade 4. Methylation testing can alert us that a tumor may have a more nefarious side."

Molecular features can help guide the aggressiveness of treatment and also might give patients access to clinical trials. "Mayo Clinic has a robust clinical trial portfolio," Dr. Burns says. "But curing brain tumors is a global effort. We have colleagues and collaborators at many other institutions. It's not uncommon for our network of colleagues around the country to help our patients gain access to each other's trials to leverage the widest array of promising options."

Clinical decision-making continues once tumors are analyzed. "There are lots of situations where it's not black and white, where there is no right or wrong answer to the questions," Dr. Burns says.

One example is the decision about prescribing vorasidenib, a relatively new medication for treating IDH-mutant tumors. "Even if there's no tumor left after gross resection of a grade 2 IDH-mutant tumor, we know it's going to come back sometime," Dr. Burns says. "Should we use vorasidenib to prevent that?"

The medication might affect patients' fertility. Although fertility-sparing procedures are possible, some patients might prefer chemotherapy and radiation therapy to avoid tumor recurrence.

Vorasidenib also might cause liver complications in some patients. "It's generally well tolerated, but you're committing patients to taking this medication potentially for many years," Dr. Burns says. "That's a source of hesitation. But what if the tumor's location means that we wouldn't have good surgical options at time of recurrence? Particularly for astrocytoma, we know that every cubic centimeter of disease left after surgery lowers that patient's probability of being alive in 15 years. If we allow the tumor to come back before we start vorasidenib, we may have given the tumor a head start. How do we balance that?

"There are several questions where the field is grappling," Dr. Burns says. "Although molecular information increasingly helps us anticipate likely tumor behavior, we still don't have a crystal ball for exactly how any given patient's tumor will behave. We really have to talk with patients about what's important to them and then discuss among ourselves."

This thoughtful analysis exemplifies Mayo Clinic's commitment to personalized cancer care. "The guiding principle throughout Mayo's history is 'the needs of the patient come first.' That's the moral compass that we as a team have at Mayo," Dr. Burns says. "It's the power of having a system built to take care of patients."

For more information

Mayo Clinic Comprehensive Cancer Center. Mayo Clinic

Refer a patient to Mayo Clinic.