@beckyboston I see this isn't opening correctly so I will copy the article here:
Medscape Medical News
Conference News
ASTRO 2025

Proton vs Photon RT in Breast Cancer: Which Is Better?
M. Alexander Otto, PA, MMSc

November 10, 2025

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Following similar results in prostate and throat cancer, a recent phase 3 trial found that proton radiotherapy (RT) failed to improve patient-reported outcomes over photon RT in women with breast cancer undergoing adjuvant radiation.

Overall, at 1- and 6-month follow-up, “there were no statistically nor clinically meaningful differences in the health-related quality of life” between photon and proton RT approaches in the RadComp trial, concluded Jose Bazan, MD, breast radiation oncologist at City of Hope National Medical Center outside Los Angeles, who discussed the findings at the American Society for Radiation Oncology (ASTRO) 2025 Annual Meeting.

Photon RT options, which included intensity-modulated RT (IMRT) and 3D conformal RT in the trial, use high-energy x-rays and are less expensive than proton RT. Although costlier, proton therapy offers greater precision: Proton beams can deposit most of their energy directly in the tumor, which can limit exposure to surrounding healthy tissue and critical organs.

Some recent studies, however, have suggested no meaningful difference in patient outcomes compared to photon therapy in other cancer types.

In localized prostate cancer, for instance, the phase 3 PARTiQol trial, reported at ASTRO 2024, found no advantage of protons over IMRT in terms of progression-free survival at 5 years or quality-of-life outcomes, including urinary, bowel, or sexual problems.

Another recent phase 3 trial, TORPEdO, found no benefit in symptom or cancer control at 1 year with protons vs IMRT in patients with oropharyngeal squamous cell carcinoma.

“Radiation oncologists have debated whether photon or proton therapy is the better choice for treating breast cancer,” principal investigator Shannon MacDonald, MD, medical director of at the Southwest Florida Proton Center in Estero, Florida, said in a press release. But “there has been little high-quality evidence to guide those decisions.”

In the current RadComp trial, researchers wanted to see whether proton RT might offer a quality-of-life advantage in breast cancer.

RadComp included 1239 women with nonmetastatic breast cancer undergoing nodal irradiation — including radiation of the internal mammary nodes — after surgery, which was mastectomy for most patients.

Patients were randomized to proton RT (n = 624) or photon RT (n = 615) at a dose of 45.0-50.4 Gy in 1.8-2.0 fractions with or without a tumor bed boost.

Several questionnaires administered at baseline, the end of treatment, and at 1- and 6-month follow-up assessed chest pain, fatigue, cosmetic satisfaction, and other metrics.

Overall, MacDonald and colleagues found no significant differences between the photon and proton groups. An early signal favoring protons for less shortness of breath lost significance after researchers corrected for the likelihood of a false-positive finding.

Cardiac and locoregional control outcomes — the trial’s primary outcomes — are pending and could take several years to report, MacDonald said.

Despite the results, RadComp did reveal that patient enthusiasm for the approach remains strong: Women treated with protons were far more likely to recommend proton therapy to others and chose it again for themselves.

At baseline in RadComp, many patients thought protons were superior to photons and would yield better outcomes, Bazan noted.

Because the trial was unblinded and patients knew when they were getting protons, the proton group’s enthusiasm likely reflects “perceptions about receiving a newer or more expensive treatment” rather than anything clinical, MacDonald said.

Overall, MacDonald concluded that “most patients could be treated with either modality and receive excellent care and have excellent long-term outcomes.”

Bazan had a different take, given the results: “X-rays should remain the predominant modality for regional lymph node irradiation” after surgery.

RadComp was funded by the Patient-Centered Outcomes Research Institute. MacDonald disclosed having commercial ties with ICOTEC and Ion Beam Associates. Bazan had no disclosures.

M. Alexander Otto is a physician assistant with a master’s degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape Medical News. Alex is also an MIT Knight Science Journalism fellow.

@beckyboston , the links works for me. Thanks for posting.