For decades, surgery has been the cornerstone of breast cancer treatment, typically followed by chemotherapy and radiation. But a new study from UT Southwestern (UTSW) is challenging this conventional approach, showing that high-dose, targeted radiation delivered before any other treatments could eliminate tumors in most women with early-stage, hormone-positive breast cancer.
Published in JAMA Network Open, the research suggests that a single, precisely guided dose of radiation may replace weeks of conventional therapy and, in some cases, remove the need for surgery altogether. Funded by the Cancer Prevention and Research Institute of Texas (CPRIT), the study is currently in Phase II trials, aiming to increase rates of complete tumor resolution.
“This opens up a whole new era,” said Dr. Asal Rahimi, UTSW professor and medical director of the Clinical Research Office at the Harold C. Simmons Comprehensive Cancer Center. “If we can determine the exact dose needed to achieve complete tumor resolution, it could fundamentally change how we treat breast cancer.”
A Shorter, Safer Treatment
The new protocol exposes 100 times less tissue to radiation than traditional methods and can be completed in a single day, compared with the usual six-week regimen. Patients can still undergo surgery if necessary, making the approach flexible and potentially less invasive.
Early-stage, hormone-positive breast cancer, which responds to estrogen or progesterone blockers, accounts for 60–70% of all breast cancer cases. In the UTSW study, participants received one concentrated radiation dose followed by roughly 10 months of hormone-blocking therapy before surgery to remove any remaining tumor tissue.
The results were striking: 72% of patients had no detectable tumor at surgery, and another 21% saw their cancer reduced by 90%. Researchers also noted that delaying surgery after radiation increased the likelihood of complete tumor disappearance, regardless of the dose or tumor size.
Potential to Transform Breast Cancer Care
Avoiding or delaying surgery could be a game-changer for patients, reducing both recovery time and the physical impact of treatment. “Much of current breast cancer research focuses on reducing the need for extensive surgery, radiation, and medication,” said Dr. Marilyn Leitch, professor and chair of breast surgery at UTSW. “It’s exciting to be part of work that can improve patients’ quality of life while minimizing treatment.”
UTSW has completed Phases I and II of the trial, with plans for a multi-institutional Phase III study. Funding remains a challenge amid tight medical research budgets, but Rahimi believes the approach is promising enough to expand.
“This could open up new, more convenient options for women with early-stage breast cancer,” Rahimi said. “It’s a major step forward, and while we are at the beginning of this journey, the potential impact is enormous.”
Though the research is still in its early stages, Rahimi calls the development the most significant achievement of her career. “It’s just the beginning, but the possibilities are incredible,” she said. “Now the real work—and the real fun—begins.”
