Breast CancerAPROOB CohortNCT07803081
Radiotherapy and Long-term Outcomes in Early Breast Cancer With SLNB Omission
An observational study of Breast Cancer and Early-Stage Invasive Breast Carcinoma, run by Samsung Medical Center at 1 site in South Korea.
Trial summary
This prospective, multicenter observational cohort study evaluates long-term outcomes in patients with early-stage invasive breast cancer who undergo breast-conserving surgery without sentinel lymph node biopsy or other axillary surgery and subsequently receive adjuvant radiotherapy. Read more about this study
- Who is it for?
- Ages 19 years and older, women only
- Conditions the study is for
- Breast Cancer, Early-Stage Invasive Breast Carcinoma
- What is being tested?
- Adjuvant Breast Radiotherapy
- Type of treatment
- Surgery or procedure
- How many people
- 500 participants
- Where
- 1 siteSouth Korea
- Study dates
- 6 Aug 2026to 5 Aug 2036
- How long will I take part?
- 5 Years
- Phase
- Observational
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 19 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Study population: Patients with histologically confirmed early-stage invasive breast cancer who have undergone breast-conserving surgery without sentinel lymph node biopsy or other axillary lymph node surgery and are scheduled to receive adjuvant radiotherapy. Eligible patients will have no evidence of distant metastasis on preoperative clinical and imaging evaluation and will be prospectively enrolled at participating institutions. Treatment decisions, including radiotherapy approach and systemic therapy, will follow routine clinical practice and will not be assigned by the study.
Who may be able to join
- Female patients aged 19 years or older with histologically confirmed invasive breast cancer
- Patients who have undergone breast-conserving surgery with curative intent
- Patients who did not undergo axillary lymph node surgery, including sentinel lymph node biopsy, at the time of breast cancer surgery
- No evidence of distant metastasis on clinical and imaging evaluation before surgery
- Planned to receive adjuvant radiotherapy after breast-conserving surgery
- Ability and willingness to provide written informed consent before study participation
Who cannot join
- Patients initially diagnosed with breast carcinoma in situ before surgery who did not undergo sentinel lymph node biopsy but were subsequently found to have invasive breast cancer on final surgical pathology
- Receipt of neoadjuvant systemic therapy before breast cancer surgery
- History of a malignancy other than breast cancer within 5 years before study enrollment, except adequately treated non-melanoma skin cancer or carcinoma in situ other than breast carcinoma in situ
- Recurrent breast cancer
- Bilateral breast cancer or inflammatory breast cancer
- Prior radiotherapy to the ipsilateral breast or chest region
- Patients considered by the investigator to be unsuitable for study participation or long-term follow-up
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
South Korea1 site, 1 recruiting
- Recruiting
Samsung Medical Center
Seoul, 05649
Haeyoung Kim, +82234102612, haeyoung0131.kim@samsung.com
Wonkyung Cho, wklove.cho@gmail.com
About this study
Official title: A Prospective Cohort Study of Radiotherapy Characteristics and Long-term Outcomes in Early Breast Cancer Omitting Sentinel Lymph Node Biopsy: The APROOB Cohort Study
This prospective, multicenter observational cohort study evaluates long-term outcomes in patients with early-stage invasive breast cancer who undergo breast-conserving surgery without sentinel lymph node biopsy or other axillary surgery and subsequently receive adjuvant radiotherapy.
The study will evaluate recurrence, survival, radiotherapy-related toxicities, and quality of life. Radiotherapy will be delivered according to routine clinical practice at each participating institution without protocol-mandated treatment assignment. Detailed radiotherapy characteristics, including treatment volume, technique, dose and fractionation, tumor-bed boost, and radiation dose to axillary lymph node levels I-III, will be prospectively collected to evaluate their associations with clinical outcomes.
Read the detailed description
Recent clinical trials have supported the omission of sentinel lymph node biopsy in selected patients with clinically node-negative early breast cancer. However, radiotherapy approaches after sentinel lymph node biopsy omission vary in routine clinical practice, and prospective data regarding the relationship between radiotherapy characteristics, radiation dose delivered to the axillary lymph nodes, and long-term clinical outcomes remain limited. Depending on patient and tumor characteristics and institutional practice, radiotherapy may include whole-breast or partial-breast irradiation with different treatment techniques, dose-fractionation schedules, and tumor-bed boost strategies. The APROOB Cohort is designed to prospectively characterize these variations and evaluate their associations with recurrence, survival, treatment-related toxicity, and quality of life following omission of sentinel lymph node biopsy. No radiotherapy technique, treatment volume, dose, or fractionation schedule is assigned by the study.
- Being tested
- Adjuvant Breast Radiotherapy
- Keywords
- Partial breast irradiation, Whole breast irradiation, Breast-conserving surgery, Sentinel lymph node biopsy omission, Radiotherapy de-escalation, Clinically node-negative breast cancer, Axillary radiation dose
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Adjuvant Breast RadiotherapyRadiation
Adjuvant radiotherapy is delivered after breast-conserving surgery according to routine clinical practice at each participating institution. Radiotherapy may include whole-breast irradiation or partial-breast irradiation, with treatment technique, dose, fractionation, and tumor-bed boost determined by the treating physician. The study does not assign or mandate a specific radiotherapy regimen.
| Study group | Role | What they receive |
|---|---|---|
| APROOB Cohort | Patients with early-stage invasive breast cancer who undergo breast-conserving surgery without sentinel lymph node biopsy or other axillary surgery and subsequently receive adjuvant radiotherapy according to routine clinical practice. Radiotherapy may include whole-breast or partial-breast irradiation, with treatment characteristics determined by the treating physician and participating institution. Receives: Radiation: Adjuvant Breast Radiotherapy |
What is being measured
The primary outcome is the main question the study is designed to answer.
5-Year Recurrence-Free Survival Rate
Recurrence-free survival is defined as the time from study enrollment to the first occurrence of ipsilateral invasive breast recurrence, ipsilateral regional lymph node recurrence, distant metastasis, or breast cancer death. The 5-year recurrence-free survival rate will be estimated using the Kaplan-Meier method.
Measured: From study enrollment to 5 years
Secondary outcomes (10)
5-Year Axillary Recurrence Rate
Axillary recurrence is defined as newly diagnosed breast cancer recurrence in the ipsilateral axillary lymph nodes after study enrollment. The 5-year cumulative incidence of axillary recurrence will be estimated.
Measured: From study enrollment to 5 years
5-Year Locoregional Recurrence Rate
Locoregional recurrence is defined as the first occurrence of one or more of the following after study enrollment: ipsilateral invasive breast recurrence; ipsilateral axillary lymph node recurrence; ipsilateral supraclavicular or infraclavicular lymph node recurrence; or ipsilateral internal mammary lymph node recurrence. The 5-year cumulative incidence will be estimated.
Measured: From study enrollment to 5 years
5-Year Distant Metastasis Rate
Distant metastasis is defined as breast cancer metastasis occurring in organs or non-regional lymph nodes outside the ipsilateral breast and ipsilateral regional lymph node regions. The 5-year cumulative incidence of the first distant metastasis after study enrollment will be estimated
Measured: From study enrollment to 5 years
5-Year Overall Survival Rate
Overall survival is defined as the time from study enrollment to death from any cause. The 5-year overall survival rate will be estimated using the Kaplan-Meier method.
Measured: From study enrollment to 5 years
Incidence of Acute Grade 2 or Higher Radiotherapy-Related Toxicity
The proportion of participants experiencing at least one grade 2 or higher acute radiotherapy-related adverse event will be assessed using the Common Terminology Criteria for Adverse Events (CTCAE), version 6.0. CTCAE grades range from 1 to 5, with higher grades indicating greater severity. Acute toxicity is defined as toxicity occurring from the start of radiotherapy through 90 days after completion of radiotherapy.
Measured: From the start of radiotherapy through 90 days after completion of radiotherapy
Incidence of Late Grade 2 or Higher Radiotherapy-Related Toxicity
The proportion of participants experiencing at least one grade 2 or higher late radiotherapy-related adverse event will be assessed using the Common Terminology Criteria for Adverse Events (CTCAE), version 6.0. CTCAE grades range from 1 to 5, with higher grades indicating greater severity. Late toxicity is defined as toxicity newly occurring or persisting more than 90 days after completion of radiotherapy.
Measured: From more than 90 days after completion of radiotherapy to 5 years after radiotherapy
Change From Baseline in Global Health Status/Quality of Life Score Assessed by the EORTC QLQ-C30
Global health status and quality of life will be assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). The Global Health Status/Quality of Life scale is transformed to a score ranging from 0 to 100. A higher score indicates better global health status and quality of life. The change from baseline will be evaluated at each scheduled follow-up assessment.
Measured: Baseline and up to 5 years after radiotherapy
Change From Baseline in Breast Symptoms Score Assessed by the EORTC QLQ-BR23
Breast symptoms will be assessed using the Breast Symptoms scale of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Breast Cancer Module 23 (EORTC QLQ-BR23). The score is transformed to a scale ranging from 0 to 100. A higher score indicates more severe breast symptoms and therefore a worse outcome. The change from baseline will be evaluated at each scheduled follow-up assessment.
Measured: Baseline and up to 5 years after radiotherapy
Change From Baseline in Arm Symptoms Score Assessed by the EORTC QLQ-BR23
Arm symptoms will be assessed using the Arm Symptoms scale of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Breast Cancer Module 23 (EORTC QLQ-BR23). The score is transformed to a scale ranging from 0 to 100. A higher score indicates more severe arm symptoms and therefore a worse outcome. The change from baseline will be evaluated at each scheduled follow-up assessment.
Measured: Baseline and up to 5 years after radiotherapy
Change From Baseline in Body Image Score Assessed by the EORTC QLQ-BR23
Body image will be assessed using the Body Image scale of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Breast Cancer Module 23 (EORTC QLQ-BR23). The score is transformed to a scale ranging from 0 to 100. A higher score indicates better body image and therefore a better outcome. The change from baseline will be evaluated at each scheduled follow-up assessment.
Measured: Baseline and up to 5 years after radiotherapy
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Sep 2026
- Study start6 Aug 2026
- Primary completion5 Aug 2036 (estimated)
- Study completion5 Aug 2036 (estimated)
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.
- More trials run by Samsung Medical CenterThe sponsor's other registered studies.
- 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
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 500 participants (estimated)
- Target duration
- 5 Years
Sponsor and investigators
- Lead sponsor
- Samsung Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Haeyoung Kim, Samsung Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07803081
- Sponsor's protocol ID
- 2026-07-140-001
- Acronym
- APROOB Cohort
- Status last verified
- Sep 2026
- First submitted
- 28 Aug 2026
- Last updated
- 3 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data are not planned to be publicly shared. Any future use or sharing of de-identified study data for additional research will be subject to applicable regulations, participant consent, and approval by the relevant institutional review boards.