No doctor likes to tell patients that they've run out of options. But when you focus on meningiomas, the most common type of tumor affecting the central nervous system, it's a conversation that happens more than you'd like, said Ben Strickland, M.D.
That's why Strickland, a neurosurgeon at MUSC Hollings Cancer Center, spends half of his time in his lab looking for novel therapies for meningiomas that don't respond to treatment. His approach mainly focuses on understanding the tumor immune microenvironment with emphasis on how the tumor is able to avoid immune cell detection and clearance.
"My clinic is full of patients with aggressive meningioma that have progressed despite multiple attempted surgeries and radiotherapy treatments. Once surgery and radiation fail, we have no other viable options currently," he said. There are no medical or chemotherapy treatments for meningioma. "So my role is to develop other options."
"It's frustrating to tell patients you don't have any other options for them. I've been here at Hollings for eight months, and I've already had a handful of patients to whom I've had to say, 'There's nothing else we can do for you.' There aren't a lot of other labs in the country actively working on meningioma, and because my focus is this tumor, and I have so many of these patients, I think it's important to be able to bridge the gap in care."
Most common central nervous system tumor
Meningiomas don't get as much publicity as other types of brain tumors – glioblastomas, for instance, are well known, especially because of high-profile patients like U.S. Senators John McCain and Ted Kennedy, both of whom died within a year of their diagnoses.
Most of the time, meningiomas are benign. But even that, Strickland said, is a misnomer.
"In the neurosurgery world, we always refer to this as a benign tumor because four out of five are relatively slow-growing – but that misses, in plain sight, that the ones that aren't slow-growing are still very common."
Meningioma, in fact, is the most common central nervous system tumor, with as many as 50,000 cases each year. It's classed as a skull base tumor, meaning it grows in the head but not in the brain itself. The meninges are tough membranes that surround and protect the brain, and this is where meningiomas develop.
About 20% are higher-grade tumors that don't respond well to the only two treatments that exist – surgery and radiation. There aren't any chemotherapy or targeted therapy options for meningioma, and few labs are studying this tumor, Strickland said.
Unfortunately, he said, malignant subtypes of meningiomas are just as progressive and often as fatal as the more studied glioblastoma.
This tumor is more common among women, Black Americans and those over age 60. Having received radiation to the head earlier in life – for instance, for retinoblastoma as a child – can lead to meningioma, as can a genetic disorder called neurofibromatosis Type 2.
Surgery is a prime treatment for this tumor, but it comes with risks – this is, after all, brain surgery. A tumor in a bad position could mean that surgery comes with a high likelihood of paralysis. At the same time, benign tumors pressing on nerves can cause symptoms ranging from seizures to behavioral changes, depending on where the tumor is.
For that reason, Strickland seeks an immunotherapy treatment that could target meningioma, whether benign or high-grade.
"If we could live in a world where we had targeted therapy for these tumors to empower the immune system so it could recognize the tumor, and we could avoid surgery altogether, that's even better," he said.
Immunotherapy research
Often, cancers give off signals that trick the immune system into leaving them alone. Immunotherapy refers to treatments that shut down or block these signals, unmasking the cancer, or that re-engineer immune cells to boost their effectiveness.
It's an approach that has been successful in some cancers and is being studied in many more, and this is the approach that Strickland is taking.
"The main idea is to figure out exactly what methods the brain tumor cells use to avoid detection by our body's normal immune system and to hopefully develop clinical trials to reverse that," he said.
There is one advantage for those few investigators looking into immunotherapy for meningioma, Strickland said. Unlike medications for tumors within the brain, which must be engineered so that they can cross the blood-brain barrier, any medications for meningioma wouldn't need to cross this barrier and could be more easily delivered.
Treatment close to home
Strickland's arrival at Hollings is a return home. He's a South Carolina native and a Clemson grad who completed neurosurgery training at the University of Southern California and a fellowship at Emory University before settling in Charleston last summer.
He's happy to be back in South Carolina and to join the state's only neuro-oncologists, Scott Lindhorst, M.D., and Alicia Zukas, M.D., in providing care to South Carolina residents close to home.
He hopes that as patients look into the program, they will see that they can get top-notch care without leaving the state.
"There's no reason to leave home," Strickland said. "Surgery's one day, but the ramifications and the effects after? It's a lot easier to tolerate if you're home. You don't need to live in an Airbnb in Houston to go to MD Anderson. Your family and your support are here, and we can offer everything that they can do."
Strickland, who treats patients with all types of brain tumors while concentrating his on meningioma, finds tremendous satisfaction serving this patient population.
"This is a vulnerable patient population. Their goals are often simply survival, so there's a lot at stake," he said. "I think it gives the job meaning."
