An interventional study of rPBI in Breast Cancer and Breast Cancer Recurrent, sponsored by University Health Network, Toronto. Recruiting at 19 sites in 10 countries. Open to female participants aged 18 Years to 99 Years. Per ClinicalTrials.gov, last updated 2026-07-17.
Sponsored by University Health Network, Toronto · Not applicable, Interventional, and Treatment
Breast-conserving surgery followed by re-irradiation with partial breast irradiation (rPBI) has recently been found to be a safe alternative to mastectomy for women who have undergone prior whole breast radiation. By reducing the volume of tissue receiving radiation, rPBI has been associated with less toxicity and improved cosmetic outcomes. For many women with early-stage breast cancer, shorter 1-week (5-fraction) courses of breast radiation (ultra-fractionation) have been found to be equivalent to longer fractionation schedules in the upfront treatment setting. These 1-week schedules are more convenient for patients, with fewer treatments and shorter overall treatment time. The investigators hypothesize that a 1-week ultra-hypofractionated rPBI regimen following breast-conserving surgery (BCS) for local recurrence or new primary breast cancer in the previously irradiated breast (LR) will be associated with acceptable toxicity at 1 year (\<13% grade >3 toxicity).
Most women affected by breast cancer are treated with breast-conserving surgery to remove the tumour, followed by radiation to reduce the risk of recurrence. Unfortunately, some women will experience recurrence of the cancer in the previously treated breast. These recurrences have historically been treated by removing the whole breast or a second breast-conserving surgery followed by 3 to 5 weeks of radiation. These treatments can negatively impact mental health and quality of life or lead to harmful side effects that could impact the skin, breast, ribs, heart and lungs.
Breast-conserving surgery followed by re-irradiation with partial breast irradiation (rPBI) has recently been found to be a safe alternative to mastectomy for women who have undergone prior whole breast radiation. By reducing the volume of tissue receiving radiation, rPBI has been associated with less toxicity and improved cosmetic outcomes. For many women with early-stage breast cancer, shorter 1-week (5-fraction) courses of breast radiation (ultra-fractionation) have been found to be equivalent to longer fractionation schedules in the upfront treatment setting. These 1-week schedules are more convenient for patients, with fewer treatments and shorter overall treatment time. The investigators hypothesize that a 1-week ultra-hypofractionated rPBI regimen following breast-conserving surgery (BCS) for local recurrence or new primary breast cancer in the previously irradiated breast (LR) will be associated with acceptable toxicity at 1 year (\<13% grade >3 toxicity).
The target population for this study is women with localized recurrent or new primary breast cancer in the previously irradiated breast. This is a prospective single arm phase 2 trial of external beam rPBI using 26Gy in 5 fractions delivered daily over 1-week after a second lumpectomy for LR following prior BCS and adjuvant whole or partial breast irradiation. Using a multi-institutional and international network of comprehensive cancer centers, this study will advance global knowledge of how to optimally treat women with this disease.
14,825 studies on the registry are indexed under Breast Neoplasms; 3,319 are open to participants now.
This study's planned enrollment of 171 is above the median of 72 across 10,896 interventional studies indexed under Breast Neoplasms.
Browse Breast Neoplasms studies →University Health Network, Toronto is the lead sponsor of 1,438 studies on the registry; 297 are open to participants now.
Of its 17 completed or terminated interventional studies of FDA-regulated products, 3 (18%) have results posted.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The US National Cancer Institute’s scale of how severe an adverse event is — any unwanted medical event during a study, such as a symptom, an illness or an abnormal test result, whether or not a treatment caused it. Whether it did is judged separately.
“Side effects of earlier treatment resolved to grade 1 or less” means they have settled to mild or gone.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adjuvant and neoadjuvant
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CTCAE grade
The US National Cancer Institute’s scale of how severe an adverse event is — any unwanted medical event during a study, such as a symptom, an illness or an abnormal test result, whether or not a treatment caused it. Whether it did is judged separately.
“Side effects of earlier treatment resolved to grade 1 or less” means they have settled to mild or gone.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
26Gy in 5 daily fractions over 1-week
Radiation: rPBI
External beam partial breast reirradiation (rPBI) using 26Gy in 5 fractions delivered daily over 1-week
Grade ≥3 toxicity associated with treatment
TThe primary endpoint, grade ≥3 toxicity associated with treatment will be summarized using frequency and percentage with 95% Clopper-Pearson confidence intervals by grade at each scheduled follow up.
Time frame: During accrual period, up to 3 years
Frequency radiation-associated toxicity (acute)
Radiation-associated toxicities (acute) will be graded according to CTCAE v5.0 by physicians. Toxicity associated with treatment will be summarized using frequency with 95% Clopper-Pearson confidence intervals by grade at each scheduled follow up.
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Percentage radiation-associated toxicity (acute)
Radiation-associated toxicities (acute) will be graded according to CTCAE v5.0 by physicians. Toxicity associated with treatment will be summarized using percentage with 95% Clopper-Pearson confidence intervals by grade at each scheduled follow up.
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Frequency radiation-associated toxicity (late)
Radiation-associated toxicities (late) will be graded according to CTCAE v5.0 by physicians. Toxicity associated with treatment will be summarized using frequency with 95% Clopper-Pearson confidence intervals by grade at each scheduled follow up.
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Percentage radiation-associated toxicity (late)
Radiation-associated toxicities (late) will be graded according to CTCAE v5.0 by physicians. Toxicity associated with treatment will be summarized using percentage with 95% Clopper-Pearson confidence intervals by grade at each scheduled follow up.
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Risk of local recurrence (invasive and DCIS)
Cumulative incidence function will be used to estimate local recurrence with death as a competing risk.
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Risk of distant recurrence (invasive and DCIS)
Cumulative incidence function will be used to estimate distant recurrence and distance recurrence with death as a competing risk.
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Location of local recurrence (in-field) (frequency)
Location of recurrence will be summarized by frequency.
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Location of local recurrence (in-field) (percentage)
Location of recurrence will be summarized by percentage.
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Location of local recurrence (out-of-field) (frequency)
Location of recurrence will be summarized by frequency.
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Location of local recurrence (out-of-field) (percentage)
Location of recurrence will be summarized by percentage
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Risk of local recurrence after rPBI requiring mastectomy
Cumulative incidence function will be used to estimate local recurrence after rPBI requiring mastectomy with death as a competing risk
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Invasive breast cancer free survival
Kaplan-Meier method will be used to estimate invasive breast cancer free survival
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Overall survival
Kaplan-Meier method will be used to estimate overall survival
Time frame: 3 months, 1 year, 2 year, 3 years, 4 years and 5 years post rPBI
Satisfaction with breasts
Quality of life questionnaire will be used to obtain scores and will summarized using mean and standard deviation at baseline and follow up. Change in score compared to baseline will be summarized using mean and standard deviation, and assessed with paired t-test. Number and proportion of patients with a minimal clinically important difference will be calculated.
Time frame: Baseline, 1 year, 3 years, and 5 years post rPBI
Financial toxicity associated with treatment
Quality of life questionnaire will be used to obtain scores and will summarized using mean and standard deviation at baseline and follow up. Change in score compared to baseline will be summarized using mean and standard deviation, and assessed with paired t-test. Number and proportion of patients with a minimal clinically important difference will be calculated.
Time frame: Baseline, 3 months, 1 year, and 3 years post rPBI
Plan to share: No
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