For all its cancer treatment advantages, the business end of proton therapy is synonymous with massive gantries and investment costs in the hundreds of millions. However, new developments from manufacturers are changing the calculus around protons, and ushering in a future where systems may require no gantry at all, and significantly lower upfront costs to providers.

P-Cure and Mevion are among the companies working to reimagine the way protons are delivered. The MEVION S250-FIT cyclotron, developed in partnership with Leo Cancer Care, is self-shielded, and the P-Cure system requires 50% less shielding than a traditional gantry room. B dot Medical in Japan also has a smaller-footprint proton therapy system called the Phemto that utilizes a much smaller gantry than traditional proton therapy. Of these systems, only P-Cure is FDA cleared and clinically available in the U.S.

As opposed to traditional proton therapy systems that treat patients in a supine position, the MEVION and P-Cure systems can treat patients upright in a chair. Rather than utilizing a gantry to rotate the beam around the patient, the beam comes from one direction and the chair rotates the patient.

"You either have the possibility to rotate the beam around the patient and keep the patient steady or to keep the beam steady and rotate the patient as you need,” explained Joern Meissner, CEO of Meissner Consulting and an expert on the subject of proton therapy installations. “The latter one does not require large magnets or large equipment and allows for smaller installations."

These upright systems have customized the robotic positioner so that the chair has six degrees of freedom, according to Meissner. Patient setup is relatively simple and imaging is integrated into the system. Administering treatment in an upright position also means there is no gravity-based organ movement, as the imaging and treatment are done in the same position, which may also offer clinical advantages.

An upright system can often fit into an existing linear accelerator (linac) vault, but Meissner explained that more often than not, the concrete contours inside the linac vault have to be modified and additional shielding may also be needed.

"For me, the upright treatment cost reduction is not so much in retrofitting an existing linac vault,” he added. “If you have an existing cancer center with a small parking lot next door, you can add proton therapy by building a quasi-linac-sized bunker for much less money than if you added even the smallest commercially-available proton bunker with a gantry.”

An existing center already comes with diagnostics, nurse stations, and all the other clinical support areas and all you have to add is a proton vault with space for the necessary auxiliary systems. In addition to reducing costs associated with the bunker size, you also reduce your operating costs, since less electricity is needed.

“You eliminate all the magnets that a gantry needs,” said Meissner. “If you don't have all the beamline magnets, that can easily result in something like a 300-kilowatt power reduction during treatment."

Doing more with what you’ve got
Alejandro Mazal, director of medical physics at Centro de Protonterapia Quironsalud in Madrid, Spain, believes upright proton systems have a place in cancer treatment, but he isn’t convinced they are the key to bringing the best care to more patients at a lower cost. At his facility, they emphasize a comprehensive approach to reducing expenses that encompasses everything from hypofractionation to optimizing the workflow.

Hypofractionation involves treating patients with higher doses of proton therapy over a shorter amount of time. For certain tumors in the base of the skull, treatment is usually done in 35 fractions, but Mazal and his team have developed a protocol that can treat some of those small tumors in five fractions.

Since the patients are being treated in a much shorter amount of time, that can drastically increase patient capacity for a proton therapy center. Mazal estimates that in the case of going from 35 to five factions, a center may be able to treat five times more patients.

“The technical capacity of a facility is not the number of patients that can be treated, it's the number of fractions that can be delivered, and that is dependent on the clinical protocols adopted for their case mix,” said Mazal.

However, hypofractionation is difficult to do for pediatric cases, which is one of the most recognized indications for proton therapy. At Mazal’s center, 50% of their patients are pediatric patients and they have no real protocols for hypofractionation.

Another thing to consider is reimbursement, as every country has a different approach. There could be a reimbursement system that pays per fraction, per patient, or a mix, which is the current model in Spain.

Keep it running
Optimizing uptime is another critical consideration for making the economics of proton therapy work. When a facility is new, the machine uptime isn’t going to be ideal, but Mazal believes that eventually it should operate with 97-98% uptime, like a conventional machine.

That’s especially important with proton therapy due to the fact that there may not be a backup system in case of a failure.

Mazal and his colleagues also analyze their facility’s workflow through all phases of treatment. They continuously monitor the time of a fraction, the pauses, the time between two patients, the system uptime, and the quality controls in order to optimize and make improvements.

They are also working with artificial intelligence programs to look at the workflow of patients. For example, they consider the placement of the waiting room and bathrooms within the facility and also whether they can analyze risks and optimize procedures.

“For every single minute you save per patient, you can treat one or two more patients per day,” said Mazal.

Ultimately, he believes that the best way to make proton therapy more affordable for existing facilities is to focus on reducing the operating costs. When it comes to making the proton therapy equipment itself more affordable, he believes that as more technological research is done, institutions such as the European Organization for Nuclear Research hold the potential to design new devices at a lower cost.

The challenge is getting the industry and research on the same page. On the research side, there are always new ideas and prototypes, but the industry needs stable products that are FDA-approved or CE-marked as medical devices.

“Somehow, we need to converge research and industry to move toward a new and cheaper version,” said Mazal. “And we need to make sure it’s stable for several years and includes the concept of reduced operating costs.”