“There is no one-size-fits-all therapy for localized kidney cancer,” says Brady urologist Nirmish Singla, M.D., M.Sc. “Surgery is the mainstay of treatment, but it may not be an option for patients who have other serious medical conditions, or complicated tumors that are deemed inoperable.” 

Similarly, nonsurgical ablative therapies aren’t a universal fit, either – particularly for patients with only one kidney or a large tumor very close to another organ, such as the bowel. 

“Recently stereotactic body radiation therapy (SBRT), using conventional x-rays, has emerged as an effective nonsurgical option for patients with early-stage renal cell carcinoma (RCC),” says radiation oncologist Curtiland Deville, M.D., of the Johns Hopkins Proton Therapy Center at Sibley Memorial Hospital’s Kimmel Cancer Center. Even so, he adds, “this can be associated with some declines in normal kidney function,” because it can damage nearby normal kidney tissue. “Proton therapy is unique in that it allows the bulk of the energy to be released at the tumor, while sparing nearby healthy tissues.” This means a lower dose of energy can be used with greater effect. 

Good news: In a single-arm Phase II study called SPARE, Brady investigators Deville, Singla, and Thomas Jarrett, M.D., Chief of Urology at Johns Hopkins Sibley Memorial Hospital, are studying a promising option for these patients: “Proton therapy is unique in that it allows the bulk of the radiation energy to be released directly at the tumor, while sparing nearby healthy tissues,” says Deville, who serves as the Principal Investigator of the trial. This means a lower dose of energy can be used with greater effect. “We hope this will better preserve long-term kidney function.” The SPARE trial (NCT06376669), supported by the Robert L. Sloan Fund for Cancer Research, is recruiting 19 patients, who will be followed for two years after treatment.