Blasting cancer patients with a beam of radiation is an imperfect science. It’s a life-saving technique that’s bound to damage healthy tissue along the way, leaving patients feeling sick or worse.
But a breakthrough device in the world of radiation treatment is practically eliminating those side effects, easing the pain that has long been a necessary part of treating cancer. The device, called Ethos, has been used on dozens of patients at El Camino Hospital, and so far the results have been a game-changer.
“There is a tremendous difference,” said Dr. Robert Sinha, El Camino’s radiation oncology medical director. “We’re just not seeing the typical side effects that we would encounter for these patients. They’re sailing through it.”
El Camino began using Ethos in April of this year, making it the first hospital in California and the fifth in the country to use the device. The futuristic-looking pentagonal machine, with its sleek backlit silver frame, serves as both a CT scanner and a linear accelerator that fires a photon beam at cancerous tumors.
What sets Ethos apart and makes such a huge difference, Sinha said, is how precisely the radiation treatment can be tailored. Rather than rely on an inflexible treatment plan over the course of several weeks, Ethos uses artificial intelligence for so-called “adaptive” radiation therapy, reflecting real-time anatomical changes for quick adjustments.
The upshot is that healthy tissue can be spared with a higher degree of accuracy than ever before, particularly for cancers where the tumor and surrounding tissue are rapidly changing.
“It’s the first system that can actually look inside the body, see what’s going on with internal anatomy and then adjust on the fly to adjust the radiation dose,” Sinha said.
Radiation therapy has come a long way in recent decades, but modern methods are still flawed. A medical team takes imaging of the tumor and typically spends three to four days of intense computer planning and optimization in order to develop a treatment plan, which is essentially set in stone for the next five to six weeks of radiation therapy. Meanwhile, the body of the patient is changing and the tumor is shrinking size, making that treatment plan less precise with each passing day and harming healthy tissue.
While less than ideal, it’s better than what was done in the 1990s. Sinha said he used to hand-draw blocks around the targeted tissue and have those drawings crafted into thick molds that would be mounted directly on the linear accelerator, creating an imprecise square beam of radiation.
“It still worked,” Sinha said. “The problem was we were hitting a lot of normal tissue.”
In the lead-up to El Camino’s purchase, Sinha said he had his eye on the new technology coming out of med-tech company Varian, based next door in Palo Alto, and made a request to the the hospital’s board of directors to purchase Ethos. The hospital has since agreed to purchase a suite of the company’s radiology products, replacing old equipment to the tune of $10.3 million.
Instead of waiting days to draft a new treatment plan, the new tech allows the medical team to do the same thing — with a greater degree of accuracy — in just a few minutes. The radiation itself is carried out through an advanced linear accelerator that can surgically adjust the beam with a “multileaf collimator,” changing the aperture of the beam similar to a camera shutter that can change angle and location.
While the machine isn’t necessary for things like brain cancer, where there isn’t a lot of movement or sudden changes in tumor size, it’s a big deal for any cancers located in or near the abdomen. The bowels and bladder are constantly changing size, making it a significant problem when traditional treatment plans lag behind or lack precision.
One of the patients treated by the machine has gone through 28 sessions for cancer that extends from her abdomen to her pelvis. In normal circumstances, Sinha said it would be one of the most difficult things the patient has ever experienced over an excruciating five-and-a-half weeks of nausea, diarrhea and other side effects. Instead, she’s had almost no problems and is finishing treatment this week.
“I have been amazed at how well she’s done,” he said. “She did phenomenal in terms of not having side effects.”
There is still some uncharted territory with the new tech. If radiation therapy can be so carefully tailored to hit cancer cells and leave healthy tissue unharmed, it’s possible that oncologists could use the opportunity to get more aggressive than ever and up the dosage.
Sinha said he’s taking a cautious approach for now. He said he knows intuitively that Ethos does open the door for greater doses with fewer side effects, but he said he’s holding off until there’s more data and more experience working with leading-edge technology that’s only been in practice for a few months.
“I’m using the tried-and-true doses that we know are going to work and are safe, but I think as time goes on we’re going to find that this is going to allow us to up the doses,” he said. “We’re going to be way less limited by healthy tissue damage.”
El Camino Hospital has invested heavily in radiation therapy in recent years, seeking to attract a larger share of the regional market with state-of-the-art technology. The new Ethos machine stands in stark contrast to older equipment, which was reportedly breaking down frequently — sometimes while the patient is in the waiting room or on the treatment table.
A report found in 2017 that 11.4% of Santa Clara County residents come to El Camino for radiation therapy, well below Kaiser (31%) and Stanford (25.4%). Hospital officials say the Ethos machine, along with a new linear accelerator and a brachytherapy device should make the hospital more competitive against larger health systems in the area. All of the new equipment marks the “latest and greatest,” Sinha said, but Ethos remains the crown jewel.