Proton Therapy for Early Stage Breast Cancer

Recruiting at 9 trial locations

Overseen By Edith Maritato

Age: 18+

Sex: Female

Trial Phase: Phase 2

Sponsor: Proton Collaborative Group

Disqualifiers: Previous breast cancer, Bilateral disease, Pregnancy, HIV/AIDS, 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

132 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests proton radiation therapy to determine its benefits for women with early-stage breast cancer. Proton therapy, a type of radiation treatment, may target cancer cells more precisely. Researchers compare its effects, both positive and negative, to assess if it offers a better treatment option. Women who have undergone a lumpectomy and have early-stage ductal breast cancer (a common type) might be suitable candidates for this trial. As a Phase 2 trial, the research focuses on measuring the treatment's effectiveness in an initial, smaller group, providing participants an opportunity to contribute to advancements in breast cancer treatment.

Do I have to stop taking my current medications for the trial?

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.

What prior data suggests that proton radiation therapy is safe for early stage breast cancer?

Research has shown that proton radiotherapy is generally safe for patients with early-stage breast cancer. A review of 32 studies involving 1,452 patients found that the treatment was well-tolerated, with patients experiencing good results and few side effects. Another study demonstrated that proton therapy can effectively control cancer while protecting nearby healthy tissue, reducing harm to unaffected areas—a significant benefit for patients.

In a large study comparing proton therapy to photon therapy (another type of radiation), patients reported excellent results with both, but many preferred proton therapy. This preference suggests that proton therapy might be gentler on the body.

Overall, earlier studies and patient experiences indicate that proton therapy is a promising and safe option for those with early-stage breast cancer. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising?

Proton radiotherapy is unique because it delivers radiation in a more precise manner than traditional X-ray radiation treatments for early-stage breast cancer. While standard treatments like conventional radiotherapy can affect healthy surrounding tissues, proton therapy targets the tumor with minimal impact on nearby healthy tissue. This precision reduces potential side effects and improves patient outcomes. Researchers are excited about proton therapy because it offers the potential for a safer, more effective treatment option by sparing healthy tissue while effectively targeting cancer cells.

What evidence suggests that proton radiation therapy might be an effective treatment for early stage breast cancer?

Research has shown that proton radiotherapy, a type of cancer treatment, may benefit women with early-stage breast cancer. This trial will evaluate proton radiotherapy, which uses the "Bragg peak" to target cancer cells more precisely while protecting healthy tissues. Studies have found that proton therapy can reduce the radiation reaching the lungs compared to other treatments, potentially leading to fewer side effects like lung inflammation. Results from 32 studies involving 1,452 patients showed excellent cancer control with proton therapy. Many patients prefer proton therapy due to its tendency to cause fewer side effects. Overall, the evidence suggests that proton radiotherapy is an effective and potentially safer option for treating early-stage breast cancer. ^{2 5 6 7 8}

Who Is on the Research Team?

Andrew Chang, MD

Principal Investigator

Proton Collaborative Group

Are You a Good Fit for This Trial?

This trial is for women aged 50 or older with early stage breast cancer (Stage 0, I, II) that's ER positive and up to 3.0 cm in size. They must have had a lumpectomy with clear margins and be able to start treatment within specific time frames post-surgery or chemotherapy. Women with invasive lobular histology, previous ipsilateral breast cancer, significant infections, certain genetic mutations like BRCA1/2, or prior chest radiation are excluded.

Inclusion Criteria

I had a lumpectomy with clear margins of at least 0.2 cm.

I understand the requirements for markers or clips for my treatment positioning.

My breast cancer is early stage (0, I, or II) and if stage II, my tumor is 3.0 cm or smaller.

Exclusion Criteria

Your pathology test shows that cancer has spread to the lymphovascular space.

Pregnant or lactating.

You have any suspicious-looking lumps or nodes that haven't been confirmed as harmless through a biopsy.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Radiation

Participants receive proton radiotherapy with 4.0 Gy (RBE) x10 fractions to a total dose of 40 Gy (RBE)

2 weeks

Follow-up

Participants are monitored for safety and effectiveness after treatment

3 years

What Are the Treatments Tested in This Trial?

Interventions

• Proton Radiotherapy

Trial Overview

The study tests the effectiveness of proton radiotherapy on women with early stage breast cancer. It aims to determine if this type of targeted radiation therapy results in fewer side effects while being as effective as traditional treatments.

How Is the Trial Designed?

Group I: Proton Radiotherapy Experimental Treatment 1 Intervention

Proton Radiotherapy 4.0 Gy (RBE) x10 fractions to 40 Gy (RBE) Total Dose

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

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]

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]

Proton beam radiation therapy may be beneficial for adolescent and young adult cancer patients by potentially reducing radiation exposure to healthy tissues, which could lower the risk of side effects after treatment.

Current literature suggests that proton therapy is effective for treating specific cancers like central nervous system tumors and Hodgkin lymphoma, but further research is needed to fully establish its role and benefits in this age group.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Proton Therapy in the Adolescent and Young Adult Population. Ahmed, SK., Keole, SR.[2023]

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]

Proton therapy offers a significant advantage in treating locally advanced breast cancer by delivering precise radiation doses that minimize damage to surrounding healthy tissues.

The review discusses important clinical and technical aspects of proton radiotherapy, emphasizing its potential to reduce treatment-related side effects for patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Potential of Proton Therapy for Locally Advanced Breast Cancer: Clinical and Technical Considerations. Lalani, N., Alqarni, S., Jimenez, RB.[2023]

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]

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]

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]

Citations

1.

pmc.ncbi.nlm.nih.gov

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

Proton Therapy in Breast Cancer: A Review of Potential ...

Proton radiotherapy may be a compelling technical option for the treatment of breast cancer due to its unique physical property known as the “Bragg peak.”

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.

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 ...

4.

pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC8416711/

Proton Therapy for Breast Cancer: A Consensus Statement ...

PT reduces the dose to the lungs in early stage and locally advanced breast cancer compared with 3DCRT and IMRT. Clinical pneumonitis is a rare complication of ...

5.

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 ...

The investigators found that both conventional and hypofractionated proton therapy resulted in excellent control of the cancer while sparing ...

6.

pmc.ncbi.nlm.nih.gov

pmc.ncbi.nlm.nih.gov/articles/PMC7615202/

Proton Beam Therapy for Early Breast Cancer - PubMed Central

Thirty-two studies (1452 patients) reported clinical outcomes after adjuvant PBT for early breast cancer. Median follow up ranged from 2-59 ...

7.

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.

8.

clinicaltrials.gov

clinicaltrials.gov/study/NCT01766297

Phase II Protocol of Proton Therapy for Partial Breast ...

The purpose of this research study is to compare the effects (good and bad) on women and their cancer using proton radiation therapy.