Awareness Efforts Aim to Improve Early Recognition and Multidisciplinary Care for Brain Tumors

Ryan Merrell, MD

Although brain tumors represent a relatively rare subset of cancers, increasing awareness among clinicians is essential to improving early recognition, diagnosis, and multidisciplinary care, according to Ryan Merrell, MD.

“Brain tumors are rare in the [general] population. However, there are many patients affected by these tumors, and in [larger geographic regions or near major cities with bigger populations], there are going to be more patients affected [each] year,” Merrell said in an interview with OncLive® during Brain Tumor Awareness Month, observed annually in May.

In the interview, Merrell detailed the key steps to arrive at a brain cancer diagnosis, highlighted the various benign and malignant subtypes that fall into this family of tumors, and detailed ongoing research that could help bring novel therapies to the glioma field.

Merrell is an associate professor of neurology and chief of the Neuro-Oncology Division at Vanderbilt-Ingram Cancer Center and Vanderbilt University Medical Center in Nashville, Tennessee.

OncLive: Why is it important to raise awareness of brain cancer among clinicians, and what role do awareness months play in highlighting its clinical relevance and prevalence?

Merrell: It's important to recognize the different kinds of brain tumors. We see ones that are benign, which [represent a significant number], and then there are the malignant [types] of brain tumors. Some people are just not aware of these tumors at all. There has been a fair amount of press coverage around brain tumors, based on celebrities or well-known individuals in the population [who have been diagnosed]. If you personally know someone with a brain tumor, you develop a tremendous connection to the people in the community [through] a great network of patients and care givers.

When a patient presents with symptoms that may raise suspicion for a possible central nervous (CNS) system mass, what is the recommended initial imaging protocol or diagnostic workup that a primary care physician should consider?

A good starting point would be a CT scan of the head because [those are typically] readily available. depending on your institution. MRI of the brain is going to be a more sensitive, higher-resolution test. Most patients who have a brain tumor ultimately will get an MRI. [Testing modality] depends on availability; if you're [at] a center that can get an MRI [done] on the same day, then I would just jump to that. If [an MRI is not immediately available], a CT scan is a good screening test, and it will tell you a lot about whether someone has a tumor.

Given the diversity of brain tumors, how do you typically approach the characterization and classification of these distinct subtypes?

One approach is to divide up tumors into benign vs malignant. It’s important to know [that in] neuro-oncology, we do take care of a large number of [patients with] benign brain tumors. The principal benign brain tumor is called meningioma. As the name implies, that's a tumor located on the surface of the brain; these are quite common in the population. Many times, patients may have a meningioma discovered incidentally—for example, they undergo an MRI for one reason, and it turns out there is a small meningioma. However, [meningiomas] can also be large, and if they are causing pressure in the brain, they may require intervention, such as surgical resection. [Meningiomas] are a significant part of the pie in terms of what we see in brain tumors.

[On] the malignant side, there's a whole spectrum. There are 3 categories that are most important to know about. One is called gliomas, and that’s where neuro-oncology is probably most recognized, because people tend to associate us with gliomas. Gliomas can be highly aggressive, like glioblastoma; lower-grade gliomas are also fairly common in our practice.

The second category would be metastatic brain tumors. These are tumors that originate elsewhere in the body and spread to the brain. The 3 most common cancers in this category are lung, breast, and melanoma. We are involved in this area, and this might be the biggest multidisciplinary area of neuro-oncology. Patients with metastatic brain tumors typically have a primary medical oncologist, a radiation oncologist, and sometimes a neurosurgeon. A neuro-oncologist like myself would be involved in their care [if the tumor spreads to the brain].

The third category of malignant brain tumors is the rarest: CNS lymphoma. This is uncommon, but at [Vanderbilt-Ingram Cancer Center], we see a fair number of these cases each year. CNS lymphoma is different from other brain tumors because it is considered a ‘liquid tumor’—meaning it falls within the leukemia/lymphoma family. Primary CNS lymphoma involves only the brain and not the rest of the body. These patients require a very unique treatment plan, but oftentimes, they respond quite well to therapy.

What is currently known about the epidemiology of brain cancer, particularly regarding the prevalence and distribution of its various subtypes?

As far as epidemiology is concerned, that is one area that we really don't know very much about. [There are] very few associations with these kinds of tumors—especially when you think about primary malignant brain tumors like gliomas. [To date], there are no identified environmental risk factors that have been definitively shown to correlate with gliomas.

The only [factors] that have really been shown to be significant are prior exposure to ionizing radiation. For example, if a patient had therapeutic radiation [during] childhood—for something like leukemia—we do see a fair number of those patients [who later develop brain tumors]. Similarly, patients who had clear exposure to radioactive sites, like a nuclear site, [may be at increased risk]. Those are really the only known environmental associations.

There are some genetic associations. For example, there are a few syndromes that carry a higher predisposition to brain tumors. One of them is Li-Fraumeni syndrome. another would be Lynch syndrome, and neurofibromatosis is also associated with a higher incidence of brain tumors.

We do hear anecdotal reports from patients who believe they’ve had [environmental] exposures [that may be linked to their tumor], and we often wonder whether there could be an association. However, it’s very difficult [to establish causality]. There have been examples of [geographic] clusters of brain tumors, and if makes you wonder if [patients] coming from a certain [geographic area] could have a common [environmental] exposure.

What therapeutic modalities are available to physicians today that have shown the most promise in the management of glioma?

For glioma specifically, the best way to simplify the treatment [approach] is that for most malignant gliomas, radiation has been shown to be effective and is still considered a gold standard—especially in high-grade gliomas like glioblastoma and grade 3 tumors. In those cases, radiation is often combined with chemotherapy. The drug many people are familiar with is temozolomide, which is still considered the standard of care in glioblastoma. [In this setting], patients typically receive 6 weeks of what’s called intensity-modulated radiation therapy combined with daily temozolomide.

Before initiating radiation, a maximal surgical resection is really important. Across all grades of gliomas. [the extent of surgical resection] has consistently been shown to be an independent prognostic factor.

Is there any ongoing research in brain cancer to watch in the near future?

One [topic] is the role of IDH inhibitors. That’s a very hot topic right now in neuro-oncology. In August [2024], a drug called vorasidenib [Voranigo] was approved [by the FDA for patients 12 years of age and older with grade 2 astrocytoma or oligodendroglioma with a susceptible IDH1 or IDH2 mutation, following surgery including biopsy, sub-total resection, or gross total resection]. [Currently], it’s approved for use in grade 2 tumors; however, there’s a broader belief in the field that its utility could extend to other types of IDH-mutated tumors.

[Accordingly], new clinical trials are being launched to evaluate IDH inhibitors in grade 3 IDH-mutated tumors and others. There are also discussions around using IDH inhibitors in settings where radiation was previously considered the standard first-line treatment. For example, in some grade 2 tumors, IDH inhibitors could potentially be used up-front, thereby allowing patients to delay or avoid radiation. That’s a significant development, and it will be a major topic at the 2025 ASCO Annual Meeting.

Another important area of focus in clinical trials is immunotherapy, which encompasses a broad spectrum of investigational approaches. Many of these studies are focused on the most aggressive tumors, like glioblastoma. In particular, there are some CAR T-cell therapy trials that have been launched recently, and those are especially interesting. I anticipate we’ll be hearing more about those at ASCO. Overall, there’s a lot happening in the immunotherapy space, and it continues to be an area of major research activity.

Reference

FDA approves vorasidenib for Grade 2 astrocytoma or oligodendroglioma with a susceptible IDH1 or IDH2 mutation. FDA. August 6, 2024. Accessed May 28, 2025. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-vorasidenib-grade-2-astrocytoma-or-oligodendroglioma-susceptible-idh1-or-idh2-mutation