Froedtert, Medical College on pace to be first to offer proton therapy in Wisconsin
Froedtert and the Medical College of Wisconsin health network are on pace to begin offering a next-level form of cancer treatment to patients as soon as August.
Earlier this month, a 2-year-long construction project to build a proton therapy clinic inside Froedtert hospital took a significant step toward completion when the final components of the cancer-treating system − an accelerator and mechanical arm weighing 15 tons − were dropped through the roof of the hospital and into a 28-foot tall by 37-foot wide, radiation-proof room.
Patients will lie down on a flat bed to receive treatment. The system provides precision treatment from every angle with 190-degree rotating mechanical arms that are mounted to a proton accelerator. The device moves around the patient behind walls. The patient will not see the accelerator or the arms moving.
The hospital partnered with Legion Healthcare Partners to bring its technology − the Mevion S250i Proton Therapy System − to its radiation clinic. The health network is not disclosing the cost of the project.
Legion first brought its technology for compact, single-room therapy systems to market in 2017.
Froedtert will be the first hospital in Wisconsin to offer proton therapy, and the 15th hospital in the country to operate the smaller therapy system. To date, the Mevion systems have treated 12,000 patients worldwide, according to Curt Kienast, Mevion Medical System's chief operating officer.
"Bringing this technology to Wisconsin, and being the first to do it, is near and dear to me," said Kienast, a Beaver Dam native. "This will be a differentiator for the region."
UW Health in Madison announced in 2022 that it also was building a proton therapy clinic, meaning Wisconsin will have two hospitals in its two largest metropolitan areas offering proton therapy within months of one another.
Patients needing proton therapy in Wisconsin now must travel to Rochester's Mayo Clinic or Northwestern Medical Group in Illinois.
What is proton therapy
Proton therapy is an advanced form of radiation therapy that more precisely delivers radiation doses to tumors.
Similar to radiation treatments that use photons, or X-rays, proton therapy also treats cancer by breaking apart the DNA strands of cancer cells, making it difficult for new cancer cells to grow.
The difference is a proton's maximal energy is absorbed at the point of contact with the tumor. Photons, or X-rays, deposit the treatment dose along the entire beam trajectory that can extend beyond the tumor, said Christopher Schultz, a radiation oncologist and chair of the Medical College of Wisconsin's Department of Radiation Oncology.
Because the proton beam largely stops once it reaches the cancerous tumor, it allows higher levels of radiation to be delivered to the tumor while not damaging adjacent organs or sensitive normal tissue, Schultz said.
"Protons go in so far and just stop on a dime," Schultz said.
Here's why that is important: Consider a 6-year-old patient with a cancerous tumor next to their spinal cord or at the base of their skull.
Because X-rays pass through the body, other organs and tissues are in the exit path of the decreasing level of radiation. The spinal cord and the brain are still growing, still developing. And while they are not the target of the radiation, they will still be exposed to some level of radiation, Schultz said.
"In some situations, you don't even want that lower level of exit dose to expose those adjacent, normal tissues to radiation, especially when treating little kids," Schultz said. "Radiation can lead to deformity or some other functional problems."
That means at some point X-ray based treatment may need to stop to prevent damage to the patient's healthy organs and tissue, Schultz said.
Froedtert and the Medical College of Wisconsin already partner with Children's Wisconsin, treating 75 to 100 of its pediatric patients at its radiation clinic each year. That partnership will continue and expand with the proton therapy, Schultz said.
Damaging adjacent tissue and organs is not an issue with proton therapy, since the radiation beam does not travel through the body, making it a beneficial form of treatment for patients who may not have had successful results with other forms of radiation treatment and whose nearby healthy organs and tissues can not be exposed to any more radiation.
"That is a big area of growth for protons - the ability to re-radiate people who are no longer progressing with their initial course of treatment," Schultz said. "You can essentially bring a (proton) dose in and put it right up to the critical, cancerous structure."
Opportunity for patients to participate in clinical trials
Schultz said clinical research suggests proton therapy is advantageous over other forms of radiation treatments when treating pediatric patients with solid organ cancers located next to growing tissues. Other studies in adults indicate proton therapy is beneficial when a tumor is located next to a critical organ.
But more research is needed into numerous types of cancers.
For now, opting for proton therapy versus other forms of image-guided radiation therapies is a decision based more on "picking the right tool out of your toolbox."
"It is not an either, or, necessarily," Schultz said. "And some of the data is still unclear as to whether or not one is better than the other. When it makes sense −and we don't know which is better − we will discuss options with the patient and put those patients on clinical trials."
Schultz said the proton clinic will reach capacity once it is treating roughly 350 patients each year. At that point, additional capacity will be added by building another room.
Jessica Van Egeren is a general assignment reporter with the Milwaukee Journal Sentinel. She can be reached at
