We are constantly asking, How can we make this better?
Linton T. Evans, MDA tiny tile that can deliver a patient’s radiation therapy while they spend quality time with loved ones. Heat-activated chemotherapies released directly at tumor sites. Unsatisfied with simply accepting what’s available, Dartmouth Cancer Center (DCC) neurosurgical oncologist Linton T. Evans, MD, is as devoted to caring for patients with brain tumors as he is to redefining what is possible for them.
Early on, as a student at Geisel School of Medicine at Dartmouth, Evans shadowed neurosurgeons at Dartmouth Hitchcock Medical Center (DHMC). “That was it,” he says. “I fell in love with the field and the kinds of patients the surgeons were seeing.”
Two mentors in particular solidified his path: section chief Nathan E. Simmons, MD, and renowned neurosurgeon David Roberts, MD, who helped pioneer image-guided and fluorescence-guided neurosurgery at Dartmouth. Evans went on to neurosurgical residency at DHMC and a neurosurgical oncology fellowship at MD Anderson Cancer Center in Texas. Today, having returned home to DCC as Director of the Brain Tumor Treatment Program, he is focused on changing one of the most difficult conversations a person can have.
A changing landscape of brain tumor care
Treatment options for brain metastases—tumors that spread to the brain from primary cancers like lung or melanoma—have improved dramatically over the past two decades, thanks to advances in surgery, radiation, immunotherapy, and targeted therapy. Evans says the focus has shifted from merely extending survival to preserving quality of life over potentially many years.
Unfortunately, the standard of care for glioblastoma—the most aggressive form of primary brain cancer—hasn’t changed much in 20 years. “But with newer technologies in the operating room, we’re better able to maximize the amount of tumor we can remove safely while being much more aware of neurocognitive outcomes,” Evans says. “We also have some exciting clinical trials on the horizon.”
Evans is proud of the growth and depth of DCC’s Brain Tumor Treatment Program for both brain metastases and primary brain tumors. “We have all the elements you’d see at major urban centers, just on a smaller scale,” he says. The multidisciplinary team includes neuro-oncologists, radiation oncologists, neurosurgeons, neuropathologists, and a dedicated neuropsychologist who studies neurocognitive outcomes in rural patients. The program’s roster of basic scientists is exploring, for example, the brain tumor immune microenvironment, how brain tumors communicate with nearby neurons, and ways to sensitize radiation-resistant tumor stem cells.
Radiation at the Time of Surgery
In 2023, Evans treated the first patient at Dartmouth Cancer Center (DCC) with GammaTile, a postage-stamp–sized device embedded with radiation seeds that can be placed directly into the brain cavity at the time of tumor surgery. Known as “brachytherapy,” the tile delivers highly localized radiation immediately after tumor removal. The benefit? Sparing healthy tissue and reducing the need for weeks of travel for radiation treatments—especially valuable for patients in rural northern New England.
DCC has now treated 15 patients with GammaTile—more than Evans initially expected. “We also participated in a multi-center clinical trial comparing GammaTile to standard post-operative radiation in patients with brain metastases, and are preparing to participate in a new trial studying the use of GammaTile for patients with newly diagnosed glioblastoma.
Having just received designation as a GammaTile Center of Excellence—one of very few in New England, Evans says “It’s exciting to see this become a real option for patients who otherwise face major travel burdens.”
Smarter, safer surgeries
Through unique collaborations, clinicians and researchers routinely connect their expertise to augment technology. “We are constantly asking, How can we make this better?” says Evans. The answer may be designing new fluorescent molecules, improving imaging probes, or leveraging machine learning to enhance image interpretation—work they hope will make brain tumor surgeries safer and more precise.
One example is the CONVIVO confocal laser microscope system, which lets neurosurgeons see cellular details of brain tissue in real time during surgery. While usually used for gliomas, “I think our team here has a different perspective about its real potential,” says Evans. He and pathologist George Zanazzi, MD, PhD, are preparing to publish their results from using the laser microscope in skull-base tumors, where achieving clear margins is critical.
Evans is also spearheading a first-in-human clinical trial concept that could extend the reach of laser interstitial thermal therapy (LITT), a minimally invasive method that involves inserting a laser fiber into the tumor and using heat delivery to destroy tumor cells. While effective, LITT has limits: heat doesn’t spread far, and nearby critical brain structures can be damaged. To overcome this, Evans is testing ThermoDox, an encapsulated chemotherapy that only activates at tumor sites when heated.
Evans is as excited about the trial as he is about how it emerged. “I was teaching a class at Thayer [Dartmouth’s School of Engineering] with fellow researcher Jack Hoopes, DVM, PhD, who told me he was ‘meeting with some folks who have a heat-sensitive chemotherapy and it might be an interesting project.’ This drug had been tried in other cancer types, but methods for monitoring the heat were still lacking. So, we met with the inventor of ThermoDox and told him we actually had a great way of measuring the amount of heat and monitoring where it was going that we use routinely, and it's this technology of using LITT with MRI (magnetic resonance imaging).”
Through DCC’s bench-to-bedside program, Evans and Hoopes secured funding to test how accurately they can predict where heat—and a drug that has never been used in the brain before—goes. While Hoopes has recently passed away, a loss deeply felt among the DCC research community, Evans will continue what they started, with hopes to finish preclinical testing, submit an application to the FDA, and launch the trial within a year. “It’s been a very rewarding collaboration,” he says, “going from hanging around after a class at Thayer to bringing safer, less toxic and more accurate and effective LITT-based treatment to patients with brain tumors.”
In addition to an environment that lends itself to fortuitous meetings, Evans credits Dartmouth’s Center for Surgical Innovation and DCC funding for “making all of this possible in a way that isn’t at other places,” he says.
Evans is also launching a fluorescence-guided surgery clinical trial for patients with newly diagnosed glioblastoma. The trial will use a novel Dartmouth-designed fluorescent dye that sharpens the contrast between tumor and healthy brain, helping surgeons remove more cancer while preserving function.
“It’s very exciting moving a molecule that was developed at Dartmouth from preclinical conception to patients,” he says. As important as the dye itself, Evans notes, is developing the systems to visualize it effectively—a task well suited to Dartmouth engineers’ tremendous expertise.
Envisioning a future
As technology improves, Evans appreciates having more nuanced conversations with patients and the expanding ability to tailor treatment plans to individual needs and preferences. “With the technology we have, we can treat patients the right way for them,” he says.
He envisions a future where improved technology and surgical precision, smarter drug delivery, and minimally invasive techniques give patients more time and better quality of life.