Partial vs Whole Breast Irradiation for Early-Stage Breast Cancer

Recruiting at 55 trial locations

Overseen By Erin McGean

Age: 18+

Sex: Female

Trial Phase: Phase 3

Sponsor: Ontario Clinical Oncology Group (OCOG)

Must be taking: Endocrine therapy

Disqualifiers: Age <50, BRCA positive, others

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

Pivotal Trial (Near Approval) This treatment is in the last trial phase before FDA approval

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

Compensation: Varies

Number of Visits: 12

Duration: 1 week

910 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests two radiation treatments for women with early-stage breast cancer. It seeks to determine if targeting only the area around the tumor (Partial Breast Irradiation or PBI) is as effective as treating the whole breast (Whole Breast Irradiation or WBI) in preventing cancer recurrence and improving breast appearance post-treatment. Women who have undergone breast-conserving surgery and have no cancer in their lymph nodes might be suitable candidates. Participants will help researchers discover if a more focused treatment can reduce side effects while preventing cancer recurrence. As a Phase 3 trial, this study represents the final step before FDA approval, offering participants a chance to contribute to potentially groundbreaking treatment advancements.

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 this trial's treatments are likely to be safe?

Research shows that Partial Breast Irradiation (PBI) might be safer for patients. One study found that PBI led to fewer serious early side effects compared to Whole Breast Irradiation (WBI), resulting in fewer severe reactions. Additionally, over 75% of patients who received PBI had excellent or good cosmetic results, indicating it is well-tolerated.

Conversely, WBI is a common treatment for early-stage breast cancer. It targets the whole breast and is often used as a standard method. While effective, the wider radiation exposure can sometimes cause more side effects.

For those considering joining a clinical trial, both treatments appear safe, with PBI possibly being a gentler option. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about Partial Breast Irradiation (PBI) and Whole Breast Irradiation (WBI) because these treatments offer more focused and potentially less invasive options for early-stage breast cancer. Unlike traditional whole breast radiation, which targets the entire breast over several weeks, these methods deliver a concentrated dose of 26 Gy in just five sessions. PBI specifically targets only the tumor bed with a margin of normal tissue, potentially reducing side effects by sparing more healthy tissue. This trial could lead to more personalized and efficient treatment plans, offering quicker recovery and potentially improved quality of life for patients.

What evidence suggests that this trial's treatments could be effective for early-stage breast cancer?

This trial will compare Partial Breast Irradiation (PBI) with Whole Breast Irradiation (WBI) for early-stage breast cancer. Research has shown that PBI works well for this condition. The Florence trial found that PBI causes fewer side effects and leads to better appearance after treatment compared to other methods. Long-term studies have demonstrated that PBI is as effective as WBI in preventing cancer recurrence. PBI also requires less time, making it more convenient. Overall, strong evidence supports PBI for women with early-stage breast cancer. ^{3 6 7 8 9}

Who Is on the Research Team?

Timothy J. Whelan

Principal Investigator

Juravinski Cancer Centre and McMaster University

Are You a Good Fit for This Trial?

This trial is for women over 50 with node-negative breast cancer that's 3cm or smaller, treated by surgery with clear margins. They must not be pregnant, lactating, BRCA positive, have a tumor larger than 3cm, multiple primary tumors in different quadrants of the same breast, a history of other cancers within the last five years (except certain skin cancers), or previous/synchronous contralateral breast cancer.

Inclusion Criteria

My underarm lymph nodes do not have cancer, confirmed by biopsy or surgery.

My breast cancer surgery removed all visible cancer with clear margins of at least 1mm.

I am a woman newly diagnosed with invasive breast cancer without spread.

Exclusion Criteria

I haven't had cancer other than non-melanoma skin cancer or in-situ carcinoma in the last 5 years.

My tumor bed cannot be seen on a CT scan.

Known pregnancy or currently lactating

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive either Partial Breast Irradiation (PBI) or Whole Breast Irradiation (WBI) with 26 Gy in 5 fractions over 5-7 days

1 week

5 visits (in-person)

Follow-up

Participants are monitored for local recurrence, cosmesis, quality of life, and other outcomes

5 years

Annually for 5 years

Radiation Toxicity Assessment

Assessment of acute and late radiation toxicity using NCI CTCAE version 5.0

3 months

2 weeks and 3 months post-radiation treatment

What Are the Treatments Tested in This Trial?

Interventions

• Partial Breast Irradiation (PBI)
• Whole Breast Irradiation (WBI)

Trial Overview The study compares Partial Breast Irradiation (PBI) to Whole Breast Irradiation (WBI) in patients after breast-conserving surgery. Both treatments are given once daily over one week. The goal is to see if PBI is as effective as WBI at preventing local recurrence and maintaining good cosmetic results three years post-treatment.

How Is the Trial Designed?

Group I: Partial Breast Irradiation (PBI) Experimental Treatment 1 Intervention

26 Gy in 5 fractions to the tumour bed with a margin of normal tissue

Group II: Whole Breast Irradiation (WBI) Active Control 1 Intervention

26 Gy in 5 fractions to the whole breast

Partial Breast Irradiation (PBI) is already approved in United States, European Union, Canada for the following indications:

Approved in United States as Partial Breast Irradiation for:

• Early-stage invasive breast cancer
• Ductal carcinoma in situ (DCIS)

Approved in European Union as Partial Breast Irradiation for:

• Early-stage invasive breast cancer
• Ductal carcinoma in situ (DCIS)

Approved in Canada as Partial Breast Irradiation for:

• Early-stage invasive breast cancer
• Ductal carcinoma in situ (DCIS)

Who Is Running the Clinical Trial?

Ontario Clinical Oncology Group (OCOG)

Lead Sponsor

Trials

65

Recruited

42,000+

GenesisCare AU

Collaborator

Trials

1

Recruited

910+

Published Research Related to This Trial

In a study of 290 patients receiving accelerated partial breast irradiation (APBI) with a median follow-up of 8 years, the rate of ipsilateral breast tumor recurrence (IBTR) was significantly higher (6.2%) compared to 1.0% in 290 patients receiving whole breast irradiation (WBI), indicating a greater risk of recurrence with APBI.

Despite the higher recurrence rates, APBI was associated with significantly fewer toxicities, such as fatigue and skin reactions, suggesting that while APBI may pose a higher risk of cancer recurrence, it offers a more tolerable treatment experience for patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Single Institution Retrospective Comparison Study of Locoregional Recurrence After Accelerated Partial Breast Irradiation Using External Beam Fractionation Compared with Whole Breast Irradiation with 8 Years of Follow-Up. Shah, S., Kyrillos, A., Kuchta, K., et al.[2018]

In a study of 131 early-stage breast cancer patients, both accelerated partial breast irradiation (APBI) and whole breast irradiation (WBI) showed similar patient-reported outcomes in terms of quality of life, pain, and fatigue after treatment, indicating both methods are effective.

Patients receiving APBI reported less skin color change and breast elevation compared to those undergoing WBI, suggesting that APBI may have a cosmetic advantage in the short term.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Patient-reported outcomes of catheter-based accelerated partial breast brachytherapy and whole breast irradiation, a single institution experience. Jethwa, KR., Kahila, MM., Mara, KC., et al.[2022]

Partial breast irradiation (PBI) is linked to a higher risk of local recurrence in early-stage breast cancer compared to whole breast irradiation (WBI), with an odds ratio of 1.69, indicating a significant concern for patients considering PBI.

Despite the increased local recurrence risk, PBI is associated with lower odds of death without breast cancer recurrence (OR 0.55), suggesting a potential survival benefit, particularly for women with smaller hormone receptor-positive tumors and no nodal involvement when treated with external beam radiation therapy (EBRT).

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Toxicity and clinical outcomes of partial breast irradiation compared to whole breast irradiation for early-stage breast cancer: a systematic review and meta-analysis. Korzets, Y., Fyles, A., Shepshelovich, D., et al.[2019]

Accelerated partial breast irradiation (APBI) is a newer treatment option that focuses on irradiating only the lumpectomy site and surrounding margin, rather than the entire breast, which has been the traditional approach for 5-7 weeks after surgery.

The review discusses the evidence from modern clinical trials supporting APBI, highlighting its potential benefits and drawbacks, as well as ongoing debates about which patient groups may benefit most from this targeted treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The evolving role of partial breast irradiation in early-stage breast cancer. Barry, M., Ho, A., Morrow, M.[2022]

Accelerated partial breast irradiation (APBI) is being investigated as a potentially effective alternative to whole-breast irradiation (WBI) for patients undergoing breast-conservation therapy (BCT).

Current clinical trials are exploring various methods of APBI to determine its safety and efficacy compared to traditional WBI, indicating a shift in treatment approaches for breast cancer.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Integrating partial breast irradiation into surgical practice and clinical trials. Fearmonti, RM., Vicini, FA., Pawlik, TM., et al.[2007]

In a study of 3009 patients treated with breast conserving therapy, both whole breast irradiation (WBI) and accelerated partial breast irradiation (APBI) showed similar long-term outcomes, with no significant differences in recurrence rates or survival after 10 years.

The analysis indicated that both treatment methods resulted in good to excellent cosmetic outcomes, with 94% of WBI patients and 95% of APBI patients reporting favorable results, suggesting that APBI can be a viable alternative to WBI without compromising effectiveness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Brachytherapy-based Accelerated Partial Breast Irradiation Provides Equivalent 10-Year Outcomes to Whole Breast Irradiation: A Matched-Pair Analysis. Wobb, JL., Shah, C., Chen, PY., et al.[2017]

Both accelerated partial-breast irradiation (APBI) techniques using 3D conformal radiation therapy (3DCRT) showed significantly improved conformity compared to conventional whole-breast irradiation (WBI) in a study involving 15 patients.

The APBI techniques maintained good dose homogeneity and did not significantly increase radiation exposure to surrounding organs at risk, indicating they are safe and effective alternatives for post-lumpectomy treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dosimetric evaluation of 3Dconformal acceleratedpartial-breast irradiation vs. whole-breast irradiation: A comparative study. Kumar, R., Sharma, SC., Kapoor, R., et al.[2021]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9685302/

Accelerated partial breast irradiation in early stage ... The Florence trial showed statistically significant less acute and late toxicity and improved cosmetic outcomes with APBI at a median follow-up of 10 years (9).

2. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC6378667/

Effectiveness of different accelerated partial breast ... This systematic review was conducted to compare the effectiveness of different accelerated partial breast irradiation (APBI) techniques for the treatment of ...

3. practicalradonc.org practicalradonc.org/article/S1879-8500(23)00296-5/fulltext

Partial Breast Irradiation for Patients With Early-Stage ... For patients with early-stage invasive breast cancer or DCIS receiving external beam PBI, 4005 cGy in 15 once daily fractions over 3 weeks is ...

4. sciencedirect.com sciencedirect.com/science/article/pii/S096097762500476X

Long-term outcomes of three distinct once-daily schedules ... Once-daily accelerated partial breast irradiation is feasible. Long term outcomes are comparable with whole breast radiotherapy. Shorter schedule (<5 fractions ...

5. abs.amegroups.org abs.amegroups.org/article/view/6912/html

Accelerated partial breast irradiation: current status and future ... There is ample evidence to support APBI for appropriately selected women with early stage breast cancer based on the available level 1 evidence as discussed.

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC7856797/

A meta-analysis of the efficacy and safety of accelerated ... Compared to whole breast irradiation, accelerated partial breast irradiation significantly reduced serious (≥ grade 2) early toxicities, ...

7. frontiersin.org frontiersin.org/journals/oncology/articles/10.3389/fonc.2022.1049704/full

Accelerated partial breast irradiation in early stage ... However, the Barcelona trial using 3D-CRT and similar fractionation to the RAPID trial showed > 75% of patients in the APBI arm had excellent or good cosmesis ...

8. ro-journal.biomedcentral.com ro-journal.biomedcentral.com/articles/10.1186/s13014-024-02412-x

Toxicity of external beam accelerated partial-breast irradiation ... External APBI demonstrated better feasibility and less toxicity than the standard regimen in the adjuvant setting for treating early breast cancer patients.

9. nature.com nature.com/articles/s41598-025-85342-2

Quality of life in early breast cancer patients after adjuvant ... Early BC patients treated with APBI showed non-inferior short-term and late HRQoL outcomes compared to hypo-WBI. In addition to previous ...