Minimally invasive stereotactic body radiation therapy
Mays Cancer Center Annual Report
“This technology is a game-changer for patients who need to travel to San Antonio. The treatment is less intrusive, and the recovery time is minimal. For loved ones, it means more time spent with family and less time worrying about treatment.”
– Christien Kluwe, MD, PhD, radiation oncologist at Mays Cancer Center
Stereotactic body radiation therapy (SBRT) uses high amounts of radiation with millimeter precision to destroy tumors in the prostate. SBRT has been around for years and is intended for patients with low- to intermediate-risk prostate cancer. Traditionally, it uses beams of energy to target tumors precisely while minimizing damage to healthy tissue. However, the latest method in treating prostate cancer has been available at Mays Cancer Center at The University of Texas Health Science Center at San Antonio since May 2023.
The latest version of the therapy is known to deliver faster and more efficient forms of radiation compared to conventional radiation treatment. Past methods required 40 to 45 daily sessions, while the newer method reduces treatment sessions to five days. SBRT is done on an outpatient basis, allowing the patient to drop in for appointments and avoid overnight stays.
“Having stereotactic body radiation therapy available for patients with prostate cancer means more access to care,” said Christien Kluwe, MD, PhD, radiation oncologist at Mays Cancer Center and assistant professor in the Department of Radiation Oncology at UT Health San Antonio.
Refining treatment through research
While SBRT represents a leap forward in efficiency and convenience, experts at Mays Cancer Center are engaged in a national clinical trial to learn the best ways to treat patients based on the severity of their disease while providing a better quality of life.
Prostate cancer patients are being diagnosed younger and living longer than ever before. Through participation in the national NRG-GU010 phase 3 clinical trial, the center is helping to determine how much treatment is truly necessary for patients with unfavorable intermediate-risk prostate cancer.
“There’s some aspect of prostate cancer where it really is a very long-term problem, and doing something today just puts a patient at risk of side effects,” said Kluwe.
As part of the trial, a biopsy from the participant’s tumor is tested for a variety of genes that can predict the risk of cancer spreading. Patients are given a score from 0–1 based on the results. A low-risk score is less than .45, an intermediate-risk score is .45–.60, and a highrisk score is more than .60.
Kluwe said the standard of care for a patient with unfavorable intermediate risk is radiation therapy and hormonal therapy based on the results of a physical exam, biopsy and blood tests. This hormone therapy, called androgen deprivation therapy, lowers the level of testosterone and dihydrotestosterone in the body. Kluwe likens it to women going through menopause. “It affects the entire body. The patients may experience fatigue, weight gain, arthritis, aches and pains in odd places, mood changes and hot flashes,” Kluwe said. “But we also know that this hormonal therapy stresses the heart. When you take away somebody’s testosterone, they are actually at increased risk for adverse cardiac events including stroke and even heart attacks.”
“When I see a guy who’s 50, I tell myself, we really have to know the best thing for him,” he said. “I expect him to live another 35 years.”
