Breast CancerPhase 3ULTIMONCT07590505
Ultrahypofractionated Versus Normofractionated Sequential Boost After Whole-breast Radiation Therapy in Patients Treated With Breast-conserving Surgery for Breast Cancer
A Phase 3 study testing Experimental - UltraHypofractionated Sequential Boost Radiation Therapy in people with Breast Cancer, run by Cancer Research Antwerp at 1 site in Belgium.
Trial summary
The ULTIMO trial is a monocentric, prospective, randomised controlled, open-label, phase III interventional clinical trial, with a non-inferiority design, in patients with breast cancer undergoing breast conservative treatment (BCT). Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Breast Cancer
- What is being tested?
- Experimental - UltraHypofractionated Sequential Boost Radiation Therapy
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 132 participants
- Where
- 1 siteBelgium
- Study dates
- 29 Mar 2022to 25 Mar 2026
- Phase
- Phase 3
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Breast cancer patients referred for WBRT + boost to the lumpectomy cavity
- Patients ≥18y
- Karnofsky Performance Score >70%, or ECOG <2
- Life expectancy of more than 5 years
- Invasive tumour free resection margins, defined as R0 resection on the pathology report
- Written informed consent
Who cannot join
- Previous contralateral breast cancer
- Previous RT of the same breast or thorax.
- Metastatic disease (M1)
Trial locations and contacts
1 site in 1 country.
About this study
The ULTIMO trial is a monocentric, prospective, randomised controlled, open-label, phase III interventional clinical trial, with a non-inferiority design, in patients with breast cancer undergoing breast conservative treatment (BCT). After giving informed consent and verifying eligibility, data collection starts and patients will be randomized in one of the following treatment arms:
- Standard treatment arm: Breast Conserving Surgery (BCS) takes place, followed by the SoC hypofractionated Whole Breast Radiation Therapy (WBRT) and SoC normofractioned sequential boost (normSEB) of 10Gy over 5 fractions.
- Experimental treatment arm: Breast Conserving Surgery (BCS) takes place, followed by the SoC hypofractionated WBRT and experimental ultrahypofractionated sequential boost (ultSEB) of 6Gy in a single fraction.
The primary objective of the ULTIMO study is to assess whether the ultSEB RT boost protocol is non-inferior to the current SoC normSEB RT boost protocol. This assessment will be based on the cosmetic outcome of the breasts, while also taking into account quality of life (QoL), the frequency and intensity of (S)AEs of interest (breast pain and fibrosis), and oncological survival.
- Conditions
- Breast Cancer
- Being tested
- Standard of Care (SOC) - Normofractionated Sequential Boost Radiation Therapy, Experimental - UltraHypofractionated Sequential Boost Radiation Therapy
- Keywords
- breast, cancer, breastcancer, radiotherapy, radiationtherapy, radiation therapy, breast conserving surgery, whole breast radiation therapy, hypofractionated boost, neoplasm
- Medical subject headings
- Breast Neoplasms, Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Standard of Care (SOC) - Normofractionated Sequential Boost Radiation TherapyRadiation
Also called normSEB
Standard of care fractionation and dosage scheme of the sequential radiation therapy boost. This consists of 5 fractions of 2Gy each, adding up to a total dose of 10Gy.
Experimental - UltraHypofractionated Sequential Boost Radiation TherapyRadiation
Also called ultSEB
The radiation therapy sequential boost is delivered in a ultrahypofractionated scheme. This consists of a single fraction of 6Gy.
| Study group | Role | What they receive |
|---|---|---|
| Standard treatment arm (SoC; Normofractionated boost RT) | Active comparator | In the control arm, the boost of the radiation therapy will be delivered according to the standard of care fractionation and dosage scheme. This consists of 5 fractions of 2Gy each, adding up to a total dose of 10Gy.
All other treatments are not considered to be study-specific and are performed according to the standard of care treatment for breast cancer. Receives: Radiation: Standard of Care (SOC) - Normofractionated Sequential Boost Radiation Therapy |
| Experimental treatment arm (Hypofractionated boost RT) | Experimental | In the experimental arm, the boost of the radiation therapy is delivered in a ultrahypofractionated scheme. This consists of a single fraction of 6Gy.
All other treatments are not considered to be study-specific and are performed according to the standard of care treatment for breast cancer. Receives: Radiation: Experimental - UltraHypofractionated Sequential Boost Radiation Therapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Cosmetic non-inferiority - BCCT.core scoring
Operationalisation:
BCCT.core is a software package for evaluating photographs of breasts after BCS. The 'Global cosmetic result' from the two frontal photos (arms up, and arms down) will be averaged and then used as the individual value of this measure. The results are scored on a 4-point Likert scale, coded as 0-3.
Analysis metric:
The change from baseline at 1 and 3YFU will be used. Negative values will be transformed to '1' to signal an inferiority event, positive or values of zero will be transformed to '0' to signal non-inferiority.
For comparisons and estimands, please refer to the SAP.
Method of aggregation:
The results will be reported as a contingency table reporting both frequencies and proportions of non-inferior and inferior results in each treatment arm.
Time point(s):
A baseline assessment is performed during the screening visit, followed by repeated measurements during the 1 and 3YFU (primary endpoint) visits.
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Cosmetic outcome - Expert panel, AIS-TAS
Operationalisation:
The AIS is a tool for scoring breast cosmesis based on standardized photos. It comprises of 5 items, each comprising of a 5 point Likert-scale, coded as 1 to 5. The score is given based on the group of photos taken at a single time point. The scores of all items are summed to produce the TAS, which consequently ranges from 5 to 25. The AIS is used in an expert panel setting, where all scores, from each assessor are averaged per item.
A higher scores represents a more favourable cosmetic outcome.
Analysis metric:
AIS-TAS absolute values will be used for analysis.
Method of aggregation:
The mean, median, SD and IQR will be reported. For comparisons and estimands, please refer to the SAP.
Time point(s):
A baseline assessment is performed during the screening visit, followed by repeated measurements during the 1 and 3YFU (primary endpoint) visits.
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Cosmetic outcome - Expert panel, AIS-Symmetry
Operationalisation:
The AIS is a tool for scoring breast cosmesis based on standardized photographs. It comprises of 5 items, each comprising of a 5 point Likert-scale, coded as 1 to 5. The score is given based on the group of photos taken at a single time point. The AIS is used in an expert panel setting, where all scores, from each assessor are averaged per item.
A higher scores represents a more favourable cosmetic outcome.
Analysis metric:
AIS-Symmetry score absolute values will be used for analysis.
Method of aggregation:
The mean, median, SD and IQR will be reported. For comparisons and estimands, please refer to the SAP.
Time point(s):
A baseline assessment is performed during the screening visit, followed by repeated measurements during the 1 and 3YFU (primary endpoint) visits.
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Secondary outcomes (14)
Cosmetic outcome - Physician scoring
Operationalisation:
The physician scoring scale (questionnaire, cfr. protocol) will be used to assess cosmetic outcome. The normalised average score of all items will be summed and used as outcome measure. This will be calculated as the score of an item divided by the amount of answering options minus 1 (k-1), averaged over all items. Some questions have the option 'not evaluable', if this answer is selected, then that item is not used in deriving the average score.
A higher scores represents a more favourable cosmetic outcome.
Analysis metric:
Absolute values will be used for analysis.
Method of aggregation:
The mean, median, SD and IQR will be reported. For comparisons and estimands, please refer to the SAP.
Time point(s):
A baseline assessment is performed during the screening visit. It is then assessed again at 1 year, and 3 years of follow-up after the last study treatment (LST).
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Cosmetic outcome - Patient reported (PROM)
Operationalisation:
The cosmetic evaluation questionnaire by Sneeuw at al. will be used to assess cosmetic outcome, as reported by the participant. The normalised average score of all items will be summed and used as outcome measure. This will be calculated as the score of an item divided by the amount of answering options minus 1 (k-1), averaged over all items.
A higher scores represents a more favourable cosmetic outcome.
Analysis metric:
Absolute values (calculated score) will be used for analysis.
Method of aggregation:
The mean, median, variance and IQR will be reported. For comparisons and estimands, please refer to the SAP.
Time point(s):
A baseline assessment is performed during the screening visit. It is then assessed again at 1 year, and 3 years of follow-up after the last study treatment (LST).
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Quality of life - EORTC QLQ C30 v3 - Global health status/QoL
Operationalisation:
The QoL (QLQ-C30) outcome variable is operationalised through the QLQ-C30 questionnaire. The answers are transformed into 3 separate scores, which can all range from 0 to 100. These scores are: Global health status/QoL, Functional scales, Symptom scales. Where a higher score on the first 2 scales indicate a better health state and QoL, while on the symptom scale a higher score indicates a higher level of disturbance by symptoms.
Analysis metric:
The QLQ-C30 Global health status absolute values will be used for analysis.
Method of aggregation:
The mean, median, SD and IQR will be reported. For comparisons and estimands, please refer to the SAP.
Time point(s):
A baseline assessment is performed during the screening visit. It is then assessed again at 1 year, and 3 years of follow-up after the last study treatment (LST).
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Quality of life - EORTC QLQ C30 v3 -Functional scales
Operationalisation:
The QoL (QLQ-C30) outcome variable is operationalised through the QLQ-C30 questionnaire. The answers are transformed into 3 separate scores, which can all range from 0 to 100. These scores are: Global health status/QoL, Functional scales, Symptom scales. Where a higher score on the first 2 scales indicate a better health state and QoL, while on the symptom scale a higher score indicates a higher level of disturbance by symptoms.
Analysis metric:
The QLQ-C30 Functional scales score absolute values will be used for analysis.
Method of aggregation:
The mean, median, SD and IQR will be reported. For comparisons and estimands, please refer to the SAP.
Time point(s):
A baseline assessment is performed during the screening visit. It is then assessed again at 1 year, and 3 years of follow-up after the last study treatment (LST).
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Quality of life - EORTC QLQ C30 v3 -Symptom scales
Operationalisation:
The QoL (QLQ-C30) outcome variable is operationalised through the QLQ-C30 questionnaire. The answers are transformed into 3 separate scores, which can all range from 0 to 100. These scores are: Global health status/QoL, Functional scales, Symptom scales. Where a higher score on the first 2 scales indicate a better health state and QoL, while on the symptom scale a higher score indicates a higher level of disturbance by symptoms.
Analysis metric:
The QLQ-C30 Symptom scales score absolute values will be used for analysis.
Method of aggregation:
The mean, median, SD and IQR will be reported. For comparisons and estimands, please refer to the SAP.
Time point(s):
A baseline assessment is performed during the screening visit. It is then assessed again at 1 year, and 3 years of follow-up after the last study treatment (LST).
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Quality of life - EORTC QLQ BR23 v1 - Functional scales
Operationalisation:
The QoL (QLQ-BR23) outcome variable is operationalised through the QLQ-BR23 questionnaire. The answers are transformed into 2 separate scores, which can both range from 0 to 100. These scores are: Functional scales; Symptom scales. Where a higher score on the functional scale indicate a better health state and QoL, while on the symptom scale a higher score indicates a higher level of disturbance by symptoms.
Analysis metric:
The QLQ-BR23 Functional scales score absolute values will be used for analysis.
Method of aggregation:
The mean, median, SD and IQR will be reported. For comparisons and estimands, please refer to the SAP.
Time point(s):
A baseline assessment is performed during the screening visit. It is then assessed again at 1 year, and 3 years of follow-up after the last study treatment (LST).
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Quality of life - EORTC QLQ BR23 v1 - Symptom scales
Operationalisation:
The QoL (QLQ-BR23) outcome variable is operationalised through the QLQ-BR23 questionnaire. The answers are transformed into 2 separate scores, which can both range from 0 to 100. These scores are: Functional scales; Symptom scales. Where a higher score on the functional scale indicate a better health state and QoL, while on the symptom scale a higher score indicates a higher level of disturbance by symptoms.
Analysis metric:
The QLQ-BR23 Symptom scales score absolute values will be used for analysis.
Method of aggregation:
The mean, median, SD and IQR will be reported. For comparisons and estimands, please refer to the SAP.
Time point(s):
A baseline assessment is performed during the screening visit. It is then assessed again at 1 year, and 3 years of follow-up after the last study treatment (LST).
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Fibrosis
Operationalisation:
During the 1Y and 3Y Follow-Up study visits the overall and tumour bed fibrosis will be scored according to the 'National Cancer Institute Common Terminology Criteria for Adverse Events' (NCI-CTCAE) v5.0 AE reporting system. This scoring will be performed by either the principal- or sub-investigators.
Analysis metric:
Tabulation of absence vs. presence and severity of fibrosis will be used for analysis.
Method of aggregation:
The proportion of participants experiencing no 'Fibrosis' vs. any 'Fibrosis' will be used. As well as the frequency of all grades, including 0 (absence).
For comparisons and estimands, please refer to the SAP.
Time point(s):
Fibrosis will be assessed and recorded during the 1YFU and 3YFU study visits.
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Breast pain
Operationalisation:
During the 1Y and 3Y Follow-Up study visits the occurrence of 'Breast pain' will be scored according to the 'National Cancer Institute Common Terminology Criteria for Adverse Events' (NCI-CTCAE) v5.0 AE reporting system. This scoring will be performed by either the principal- or sub-investigators.
Analysis metric:
Tabulation of absence vs. presence and severity of 'Breast pain' will be used for analysis.
Method of aggregation:
The proportion of participants experiencing no 'Breast pain' vs. any 'Breast pain' will be used. As well as the frequency of all grades, including 0 (absence).
For comparisons and estimands, please refer to the SAP.
Time point(s):
Fibrosis will be assessed and recorded during the 1YFU and 3YFU study visits.
Measured: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Oncological survival and time-to-event data - Overall Survival (OS)
Operationalisation:
The oncological survival and TTE data are operationalised as time-to-event intervals for the events of interest listed below.
The 'OS' TTE/survival outcome will be reported according to the 2015 DATECAN consensus, including time-to-event data for the following events of interest: 'Death from any cause'.
Analysis metric:
The TTE data is registered in days from randomisation (Rz). Censoring will be used for participants without events at the end of their follow up.
Method of aggregation:
KM-estimates, as well as proportions free from events at follow-up visit timepoints will be reported. The non-aggregated data will be used for survival analysis. For comparisons and estimands, please refer to the SAP.
Measured: Oncological TTE data will be registered at 1 and 3 years of follow-up after the last study treatment (LST). However, the exact dates of diagnosis/death will be used.
Oncological survival and time-to-event data - Breast Cancer-Specific Survival (BCSS)
Operationalisation:
The oncological survival and TTE data are operationalised as time-to-event intervals for the events of interest listed below.
The 'BCSS' TTE/survival outcome will be reported according to the 2015 DATECAN consensus, including time-to-event data for the following events of interest: 'Death from breast cancer'.
Analysis metric:
The TTE data is registered in days from randomisation (Rz). Censoring will be used for participants without events at the end of their follow up.
Method of aggregation:
KM-estimates, as well as proportions free from events at follow-up visit timepoints will be reported. The non-aggregated data will be used for survival analysis. For comparisons and estimands, please refer to the SAP.
Measured: Oncological TTE data will be registered at 1 and 3 years of follow-up after the last study treatment (LST). However, the exact dates of diagnosis/death will be used.
Oncological survival and time-to-event data - Relapse-Free Survival (RFS)
Operationalisation:
The oncological survival and TTE data are operationalised as time-to-event intervals for the events of interest listed below.
The 'RFS' TTE/survival outcome will be reported according to the 2015 DATECAN consensus, including time-to-event data for the following events of interest: 'Death from any cause', 'Invasive ipsilateral breast tumor recurrence', 'Local Invasive recurrence', 'Regional Invasive recurrence', 'occurrence of metastases', or 'Ipsilateral DCIS'.
Analysis metric:
The TTE data is registered in days from randomisation (Rz). Censoring will be used for participants without events at the end of their follow up.
Method of aggregation:
KM-estimates, as well as proportions free from events at follow-up visit timepoints will be reported. The non-aggregated data will be used for survival analysis. For comparisons and estimands, please refer to the SAP.
Measured: Oncological TTE data will be registered at 1 and 3 years of follow-up after the last study treatment (LST). However, the exact dates of diagnosis/death will be used.
Oncological survival and time-to-event data - Locoregional Relapse-Free Survival (L-RFS)
Operationalisation:
The oncological survival and TTE data are operationalised as time-to-event intervals for the events of interest listed below.
The 'L-RFS' TTE/survival outcome will be reported according to the 2015 DATECAN consensus, including time-to-event data for the following events of interest: 'Death from any cause', 'Invasive ipsilateral breast tumor recurrence', 'Local Invasive recurrence', 'Regional Invasive recurrence', or 'Ipsilateral DCIS'.
Analysis metric:
The TTE data is registered in days from randomisation (Rz). Censoring will be used for participants without events at the end of their follow up.
Method of aggregation:
KM-estimates, as well as proportions free from events at follow-up visit timepoints will be reported. The non-aggregated data will be used for survival analysis. For comparisons and estimands, please refer to the SAP.
Measured: Oncological TTE data will be registered at 1 and 3 years of follow-up after the last study treatment (LST). However, the exact dates of diagnosis/death will be used.
Oncological survival and time-to-event data - Distant-Relapse Free Survival (D-RFS)
Operationalisation:
The oncological survival and TTE data are operationalised as time-to-event intervals for the events of interest listed below.
The 'D-RFS' TTE/survival outcome will be reported according to the 2015 DATECAN consensus, including time-to-event data for the following events of interest: 'Death from any cause', or 'occurrence of metastases'.
Analysis metric:
The TTE data is registered in days from randomisation (Rz). Censoring will be used for participants without events at the end of their follow up.
Method of aggregation:
KM-estimates, as well as proportions free from events at follow-up visit timepoints will be reported. The non-aggregated data will be used for survival analysis. For comparisons and estimands, please refer to the SAP.
Measured: Oncological TTE data will be registered at 1 and 3 years of follow-up after the last study treatment (LST). However, the exact dates of diagnosis/death will be used.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 May 2026
- Study start29 Mar 2022
- Primary completion28 Nov 2025
- Study completion25 Mar 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- The ULTIMO trial is a prospective, interventional, randomised (RCT), phase 3, open label clinical trial.
- Masking
- None (open label)
- Enrolment
- 132 participants (actual)
Sponsor and investigators
- Lead sponsor
- Cancer Research Antwerp
- Sponsor type
- University, hospital or other
- Collaborators
- Ziekenhuis aan de Stroom, Gasthuis Zusters Antwerpen, Iridium netwerk
- Responsible party
- Sponsor
- Investigators
- Melanie Machiels, MD, PhD, Principal investigator, Iridium netwerk
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07590505
- Sponsor's protocol ID
- CTO21030GZA
- Acronym
- ULTIMO
- Status last verified
- Jul 2026
- First submitted
- 6 May 2026
- Last updated
- 29 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: There is no current plan to share IPD. If sharing IPD could help our scientific knowledge/understanding, it could be considered. Before IPD is shared, a motivated request, ethical commission approval and a signed DTA is needed.
Study at a glance
From the registry record, last updated by the sponsor on 29 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Ultrahypofractionated Versus Normofractionated Sequential Boost After Whole-breast Radiation Therapy in Patients Treated With Breast-conserving Surgery for Breast Cancer
- ClinicalTrials.gov ID
- NCT07590505
- Acronym / sponsor ID
- ULTIMO / CTO21030GZA
- Conditions
- Breast Cancer
- Keywords
- breast, cancer, breastcancer, radiotherapy, radiationtherapy, radiation therapy, breast conserving surgery, whole breast radiation therapy
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 132 participants (actual)
- Lead sponsor
- Cancer Research AntwerpUniversity, hospital or other
- Collaborators
- Ziekenhuis aan de Stroom, Gasthuis Zusters Antwerpen, Iridium netwerk
- Study start
- 29 Mar 2022 (actual)
- Primary completion
- 28 Nov 2025 (actual)
- Study completion
- 25 Mar 2026 (actual)
- First posted
- 15 May 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The ULTIMO trial is a monocentric, prospective, randomised controlled, open-label, phase III interventional clinical trial, with a non-inferiority design, in patients with breast cancer undergoing breast conservative treatment (BCT). After giving informed consent and verifying eligibility, data collection starts and patients will be randomized in one of the following treatment arms:
- Standard treatment arm: Breast Conserving Surgery (BCS) takes place, followed by the SoC hypofractionated Whole Breast Radiation Therapy (WBRT) and SoC normofractioned sequential boost (normSEB) of 10Gy over 5 fractions.
- Experimental treatment arm: Breast Conserving Surgery (BCS) takes place, followed by the SoC hypofractionated WBRT and experimental ultrahypofractionated sequential boost (ultSEB) of 6Gy in a single fraction.
The primary objective of the ULTIMO study is to assess whether the ultSEB RT boost protocol is non-inferior to the current SoC normSEB RT boost protocol. This assessment will be based on the cosmetic outcome of the breasts, while also taking into account quality of life (QoL), the frequency and intensity of (S)AEs of interest (breast pain and fibrosis), and oncological survival.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- The ULTIMO trial is a prospective, interventional, randomised (RCT), phase 3, open label clinical trial.
| Arm | Type | Receives |
|---|---|---|
| Standard treatment arm (SoC; Normofractionated boost RT) | Active comparator | Radiation: Standard of Care (SOC) - Normofractionated Sequential Boost Radiation TherapyIn the control arm, the boost of the radiation therapy will be delivered according to the standard of care fractionation and dosage scheme. This consists of 5 fractions of 2Gy each, adding up to a total dose of 10Gy. All other treatments are not considered to be study-specific and are performed according to the standard of care treatment for breast cancer. |
| Experimental treatment arm (Hypofractionated boost RT) | Experimental | Radiation: Experimental - UltraHypofractionated Sequential Boost Radiation TherapyIn the experimental arm, the boost of the radiation therapy is delivered in a ultrahypofractionated scheme. This consists of a single fraction of 6Gy. All other treatments are not considered to be study-specific and are performed according to the standard of care treatment for breast cancer. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Breast cancer patients referred for WBRT + boost to the lumpectomy cavity
- Patients ≥18y
- Karnofsky Performance Score >70%, or ECOG <2
- Life expectancy of more than 5 years
- Invasive tumour free resection margins, defined as R0 resection on the pathology report
Key exclusion criteria (3 listed)
- Previous contralateral breast cancer
- Previous RT of the same breast or thorax.
- Metastatic disease (M1)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Standard of Care (SOC) - Normofractionated Sequential Boost Radiation TherapyAlso: normSEBStandard of care fractionation and dosage scheme of the sequential radiation therapy boost. This consists of 5 fractions of 2Gy each, adding up to a total dose of 10Gy. | Radiation | Standard treatment arm (SoC; Normofractionated boost RT) |
| Experimental - UltraHypofractionated Sequential Boost Radiation TherapyAlso: ultSEBThe radiation therapy sequential boost is delivered in a ultrahypofractionated scheme. This consists of a single fraction of 6Gy. | Radiation | Experimental treatment arm (Hypofractionated boost RT) |
Primary outcome
Cosmetic non-inferiority - BCCT.core scoring
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Operationalisation: BCCT.core is a software package for evaluating photographs of breasts after BCS. The 'Global cosmetic result' from the two frontal photos (arms up, and arms down) will be averaged and then used as the individual value of this measure. The results are scored on a 4-point Likert scale, coded as 0-3. Analysis metric: The change from baseline at 1 and 3YFU will be used. Negative values will be transformed to '1' to signal an inferiority event, positive or values of zero will be transformed to '0' to signal non-inferiority. For comparisons and estimands, please refer to the SAP. Method of aggregation: The results will be reported as a contingency table reporting both frequencies and proportions of non-inferior and inferior results in each treatment arm. Time point(s): A baseline assessment is performed during the screening visit, followed by repeated measurements during the 1 and 3YFU (primary endpoint) visits.
Cosmetic outcome - Expert panel, AIS-TAS
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Operationalisation: The AIS is a tool for scoring breast cosmesis based on standardized photos. It comprises of 5 items, each comprising of a 5 point Likert-scale, coded as 1 to 5. The score is given based on the group of photos taken at a single time point. The scores of all items are summed to produce the TAS, which consequently ranges from 5 to 25. The AIS is used in an expert panel setting, where all scores, from each assessor are averaged per item. A higher scores represents a more favourable cosmetic outcome. Analysis metric: AIS-TAS absolute values will be used for analysis. Method of aggregation: The mean, median, SD and IQR will be reported. For comparisons and estimands, please refer to the SAP. Time point(s): A baseline assessment is performed during the screening visit, followed by repeated measurements during the 1 and 3YFU (primary endpoint) visits.
Cosmetic outcome - Expert panel, AIS-Symmetry
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Operationalisation: The AIS is a tool for scoring breast cosmesis based on standardized photographs. It comprises of 5 items, each comprising of a 5 point Likert-scale, coded as 1 to 5. The score is given based on the group of photos taken at a single time point. The AIS is used in an expert panel setting, where all scores, from each assessor are averaged per item. A higher scores represents a more favourable cosmetic outcome. Analysis metric: AIS-Symmetry score absolute values will be used for analysis. Method of aggregation: The mean, median, SD and IQR will be reported. For comparisons and estimands, please refer to the SAP. Time point(s): A baseline assessment is performed during the screening visit, followed by repeated measurements during the 1 and 3YFU (primary endpoint) visits.
14 secondary outcomes
Cosmetic outcome - Physician scoring
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Cosmetic outcome - Patient reported (PROM)
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Quality of life - EORTC QLQ C30 v3 - Global health status/QoL
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Quality of life - EORTC QLQ C30 v3 -Functional scales
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Quality of life - EORTC QLQ C30 v3 -Symptom scales
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Quality of life - EORTC QLQ BR23 v1 - Functional scales
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Quality of life - EORTC QLQ BR23 v1 - Symptom scales
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Fibrosis
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Breast pain
Time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.
Oncological survival and time-to-event data - Overall Survival (OS)
Time frame: Oncological TTE data will be registered at 1 and 3 years of follow-up after the last study treatment (LST). However, the exact dates of diagnosis/death will be used.
Oncological survival and time-to-event data - Breast Cancer-Specific Survival (BCSS)
Time frame: Oncological TTE data will be registered at 1 and 3 years of follow-up after the last study treatment (LST). However, the exact dates of diagnosis/death will be used.
Oncological survival and time-to-event data - Relapse-Free Survival (RFS)
Time frame: Oncological TTE data will be registered at 1 and 3 years of follow-up after the last study treatment (LST). However, the exact dates of diagnosis/death will be used.
Oncological survival and time-to-event data - Locoregional Relapse-Free Survival (L-RFS)
Time frame: Oncological TTE data will be registered at 1 and 3 years of follow-up after the last study treatment (LST). However, the exact dates of diagnosis/death will be used.
Oncological survival and time-to-event data - Distant-Relapse Free Survival (D-RFS)
Time frame: Oncological TTE data will be registered at 1 and 3 years of follow-up after the last study treatment (LST). However, the exact dates of diagnosis/death will be used.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Jul 2026.
- This link refers to the video abstract of the interim analysis presented at the San-Antonio Breast Cancer meeting in 2024.Link provided by the sponsor.
- Individual participant dataSharing planned: Undecided. There is no current plan to share IPD. If sharing IPD could help our scientific knowledge/understanding, it could be considered. Before IPD is shared, a motivated request, ethical commission approval and a signed DTA is needed.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Melanie Machiels, MD, PhD principal investigator
Iridium netwerk
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Experimental - UltraHypofractionated Sequential Boost Radiation Therapy in people with Breast Cancer, run by Cancer Research Antwerp at 1 site in Belgium.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 29 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Cosmetic non-inferiority - BCCT.core scoring (time frame: From enrollment to the end of follow-up at 3 years of follow-up, counting from the last study visit.). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Jul 2026.