Proton Radiation for Breast Cancer

Not currently recruiting at 5 trial locations

Age: 18+

Sex: Any

Trial Phase: Phase 2

Sponsor: Proton Collaborative Group

Disqualifiers: Weight, Prior radiation, Pregnancy, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Prior Safety Data This treatment has passed at least one previous human trial

Approved in 4 Jurisdictions This treatment is already approved in other countries

Compensation: Varies

Number of Visits: Unknown

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores the safety and potential long-term side effects of proton radiotherapy (also known as proton radiation therapy) for women with advanced breast cancer that has spread to nearby areas. Researchers focus on how this treatment might impact heart health and the risk of developing new cancers over time. Women who have undergone surgery for invasive breast cancer and meet certain criteria, such as having had a lumpectomy or mastectomy, may qualify. As a Phase 2 trial, this research measures the treatment's effectiveness in an initial, smaller group, allowing participants to contribute to significant advancements in breast cancer therapy.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

Is there any evidence suggesting that proton radiotherapy is likely to be safe for humans?

Research has shown that proton radiotherapy for breast cancer is generally manageable for patients. In one study where patients received proton beam radiation, only one person experienced serious lung problems, indicating a low risk of lung damage.

Other studies have compared proton therapy to traditional radiation treatments. Both methods are effective, but proton therapy is slightly preferred due to fewer side effects.

Additionally, research from the Mayo Clinic suggested that proton therapy might allow for a shorter treatment time for breast cancer patients without compromising safety.

These findings indicate that proton radiotherapy is a safe option with minimal side effects for women with breast cancer. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

Proton radiotherapy is unique because it uses protons instead of traditional X-rays to target breast cancer tumors. Unlike standard radiation therapy, which often affects surrounding healthy tissues, proton therapy delivers more precise doses of radiation directly to the tumor with minimal impact on nearby organs. Researchers are excited about this treatment because it has the potential to reduce side effects and improve the quality of life for patients while maintaining effective cancer control.

What evidence suggests that proton radiotherapy might be an effective treatment for breast cancer?

Studies have shown that proton radiotherapy, which participants in this trial will receive, can effectively treat breast cancer while minimizing harm to nearby tissues. One study found that a shorter schedule of proton therapy controlled cancer effectively and protected surrounding healthy tissue. Another large study reported that patients who received proton therapy experienced excellent results and preferred it over traditional treatments. Additionally, early findings suggest that proton therapy might reduce long-term side effects compared to other treatments while maintaining similar cure rates. This evidence indicates that proton radiotherapy could offer positive outcomes for women with advanced breast cancer. ^{2 5 6 7 8}

Who Is on the Research Team?

Eugen Hug, MD

Principal Investigator

Proton Collaborative Group

Are You a Good Fit for This Trial?

This trial is for women over 18 with stage II/III breast cancer who've had surgery like a mastectomy or lumpectomy. They should expect to live at least another 10 years and agree to use non-hormonal contraception if of childbearing potential. Excluded are those with certain psychiatric, collagen diseases, pregnancy, weight over 410 pounds, large breast size unsuitable for treatment setup, prior non-breast cancers (with exceptions), unclear surgical margins without re-excision clearance, temporary breast expanders depending on assessment, previous chest radiation therapy, non-epithelial breast malignancies or a history of breast cancer.

Inclusion Criteria

I have multicentric breast cancer or Paget's disease of the nipple.

I have undergone surgery for breast cancer, like mastectomy or lumpectomy.

My breast cancer is confirmed by tests and is of a specific type (invasive ductal or lobular).

Exclusion Criteria

Your breast size is too large for the treatment setup process.

Psychiatric or addictive disorders or other conditions that, in the opinion of the investigator, would preclude the patient from meeting the study requirements.

I have had radiation therapy to my chest area before.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Radiation

Participants receive postoperative, cardiac-sparing proton radiotherapy for loco-regional breast cancer

6-8 weeks

Follow-up

Participants are monitored for safety and effectiveness, focusing on cardiac mortality and second malignant neoplasms

10-15 years

What Are the Treatments Tested in This Trial?

Interventions

• Proton Radiotherapy

Trial Overview The study tests postoperative proton radiotherapy's safety and long-term effects in advanced-stage breast cancer patients. It aims to monitor acute side effects and the risk of heart-related deaths and secondary cancers after up to 15 years following treatment.

How Is the Trial Designed?

Group I: Proton Radiotherapy Experimental Treatment 1 Intervention

Proton Radiotherapy

Proton Radiotherapy is already approved in United States, European Union, Canada, Japan for the following indications:

Approved in United States as Proton Therapy for:

• Early-stage breast cancer
• Locally advanced breast cancer
• Recurrent breast cancer

Approved in European Union as Proton Therapy for:

• Breast cancer
• Early-stage breast cancer
• Locally advanced breast cancer

Approved in Canada as Proton Therapy for:

• Breast cancer
• Early-stage breast cancer

Approved in Japan as Proton Therapy for:

• Breast cancer

Who Is Running the Clinical Trial?

Proton Collaborative Group

Lead Sponsor

Trials

10

Recruited

41,100+

Published Research Related to This Trial

In a phase II trial involving 50 women with early-stage breast cancer, proton beam irradiation for partial breast radiotherapy after lumpectomy demonstrated excellent safety, with minimal treatment-related toxicities such as mild radiation dermatitis and no serious complications like infections or cardiac events.

The treatment showed high efficacy, with 5-year overall survival and disease-free survival rates of 96% and 92%, respectively, and no local failures, indicating that proton therapy is a promising option for breast cancer treatment with reduced risk to surrounding healthy tissues.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Partial breast irradiation delivered with proton beam: results of a phase II trial. Bush, DA., Slater, JD., Garberoglio, C., et al.[2018]

Proton therapy is being explored as a treatment option for breast cancer due to its ability to reduce radiation exposure to the heart and lungs while improving coverage of the tumor target.

This report provides a technical guide and patient selection algorithm to optimize the safe and effective use of passive-scattering proton therapy for breast cancer treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Technical Guide for Passive Scattering Proton Radiation Therapy for Breast Cancer. Bradley, JA., Ho, MW., Li, Z., et al.[2020]

Adjuvant proton beam therapy (PBT) for early breast cancer has been studied in 32 trials involving 1452 patients, showing that it may lead to fewer severe adverse events compared to traditional photon radiation therapy, particularly with scanning PBT.

The most common severe adverse effect reported after scanning PBT was dermatitis, affecting 5.7% of patients, while other severe outcomes like infection and pain were less frequent, indicating a generally favorable safety profile for PBT.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Proton Beam Therapy for Early Breast Cancer: A Systematic Review and Meta-analysis of Clinical Outcomes. Holt, F., Probert, J., Darby, SC., et al.[2023]

In a study of 30 breast cancer patients treated with postoperative proton therapy, the treatment was well tolerated, with a median dose of 50.4 Gy delivered over 5 weeks and no patients requiring a treatment break.

While 71.4% of patients experienced grade 2 dermatitis and 28.6% had grade 2 esophagitis, the therapy effectively spared normal tissues, showing a median heart dose of only 0.88 Gy, indicating a favorable safety profile.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Early toxicity in patients treated with postoperative proton therapy for locally advanced breast cancer. Cuaron, JJ., Chon, B., Tsai, H., et al.[2018]

Proton beam radiation therapy for early-stage breast cancer may improve cosmetic outcomes by delivering a lower dose to non-target breast tissue during partial breast irradiation, although more research is needed to confirm these benefits.

In patients with locally advanced breast cancer, proton therapy shows a better dosimetric profile compared to traditional photon and electron techniques, with early clinical results indicating acceptable levels of toxicity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Novel applications of proton therapy in breast carcinoma. Cuaron, JJ., MacDonald, SM., Cahlon, O.[2018]

In a phase II trial involving 38 women with early-stage breast cancer, proton therapy for partial breast irradiation achieved 100% cancer control over a median follow-up of 35 months, indicating its efficacy.

The treatment resulted in minimal adverse effects, with no severe toxicities reported, and patient-reported quality of life remained stable, supporting proton therapy as a safe option for breast cancer treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Outcomes and toxicities after proton partial breast radiotherapy for early stage, hormone receptor positive breast cancer: 3-Year results of a phase II multi-center trial. Choi, JI., Prabhu, K., Hartsell, WF., et al.[2022]

Proton beam radiotherapy (PBT) for breast cancer shows promising results, with skin toxicity rates (grade 1 dermatitis at ~25% and grade 2 dermatitis at 71-75%) comparable or better than traditional photon therapy.

PBT has the potential to significantly reduce cardiac risks by keeping the mean heart dose at ≤ 1 Gy, although more definitive clinical data is needed, and ongoing randomized trials will help clarify its efficacy compared to photon therapy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Clinical Outcomes and Toxicity of Proton Radiotherapy for Breast Cancer. Verma, V., Shah, C., Mehta, MP.[2022]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10894553/

Proton Therapy in Breast Cancer: A Review of Potential ... Outcomes of proton therapy on breast cancer patients. 46% (19/41) acute G ≥ 2 RD in the conventional fractionation group and 17% (7/41) in the ...

2. astro.org astro.org/news-and-publications/news-and-media-center/news-releases/2025/first-randomized-study-comparing-proton-and-photon-radiation-therapy-for-breast-cancer-finds-both-pr

First randomized study comparing proton and photon ... Large phase III trial shows patients report excellent outcomes after either treatment, with differences in preference favoring protons.

3. cancerblog.mayoclinic.org cancerblog.mayoclinic.org/2023/10/10/mayo-clinic-study-reveals-proton-beam-therapy-may-shorten-breast-cancer-treatment/

Mayo Clinic study reveals proton beam therapy may ... A condensed hypofractionated schedule of proton therapy resulted in excellent control of cancer while sparing surrounding tissue.

4. redjournal.org redjournal.org/article/S0360-3016(23)00168-2/fulltext

Proton Beam Therapy for Early Breast Cancer Thirty-two studies (1452 patients) reported clinical outcomes after adjuvant PBT for early breast cancer. Median follow-up ranged from 2 to 59 ...

5. pennmedicine.org pennmedicine.org/news/patient-powered-proton-study-looks-at-long-term-side-effects

Patient-powered proton study looks at long-term side effects The RadComp study asks, could proton therapy reduce some long-term side effects while maintaining comparable cure rates to traditional ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11496198/

Proton therapy for breast cancer: Reducing toxicity - PMC A prospective study 48 of proton beam radiation in patients undergoing RNI showed encouragingly low levels of lung damage, with only one ...

7. cancer.gov cancer.gov/news-events/cancer-currents-blog/2020/proton-therapy-safety-versus-traditional-radiation

Is Proton Therapy Safer than Traditional Radiation? - NCI After 3 years, 46% of patients in the proton therapy group and 49% of those in the traditional radiation therapy group were cancer free. Fifty- ...

8. newsnetwork.mayoclinic.org newsnetwork.mayoclinic.org/discussion/new-mayo-clinic-study-reveals-proton-beam-therapy-may-shorten-breast-cancer-treatment/

Mayo Clinic study reveals proton beam therapy may ... Mayo Clinic Comprehensive Cancer Center researchers uncover evidence supporting a shorter treatment time for breast cancer patients.