An observational study in Breast Cancer and Early-Stage Invasive Breast Carcinoma, sponsored by Samsung Medical Center. Recruiting at 1 site in South Korea. Open to female participants aged 19 Years and older. Per ClinicalTrials.gov, last updated 2026-09-03.
Sponsored by Samsung Medical Center · Observational
Among 46 studies in Breast Neoplasms by Samsung Medical Center — 13 open to participants now, 15 under way, 1 of them phase 3. Breast Neoplasms · Samsung Medical Center.
Among the 46 studies in Breast Neoplasms by Samsung Medical Center, this one is the 7th largest by planned enrollment of the 18 observational ones that give a count, is one of 2 that started in 2026, is one of 18 observational ones, reaches primary completion later than 14 of the 14 other live ones, and was the 46th registered.
14,825 studies on the registry are indexed under Breast Neoplasms; 3,319 are open to participants now.
Browse Breast Neoplasms studies →13 of the 46 studies in Breast Neoplasms by Samsung Medical Center are open now, in 1 country. Recruiting first, the newest first:
Samsung Medical Center · Sites in Korea, Republic of
Samsung Medical Center · Sites in Korea, Republic of
Samsung Medical Center · Sites in Korea, Republic of
Samsung Medical Center · Sites in Korea, Republic of
Samsung Medical Center · Sites in Korea, Republic of
By country, each count listing its studies:
Of the 2,400 Breast Neoplasms studies recruiting now, 1,572 (66%) set no upper age limit and 591 (25%) stop at 75 or younger; 103 take children under 18; 214 take healthy volunteers.
This study: 19 Years and older · female · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
46 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 1 · Phase 2 7 · Phase 3 3 · Phase 4 1
First in 2007; this study’s year is marked. 2 started in 2026.
This study's planned enrollment of 500 is above the median of 184 across 3,235 observational studies indexed under Breast Neoplasms.
Median enrollment 147 across the 27 interventional studies, 375 across the 18 observational. Of the 12 that completed or were terminated, 0 (0%) have results posted.
This tab as a report to print or save as PDF → With an account.
Samsung Medical Center is the lead sponsor of 1,011 studies on the registry; 152 are open to participants now.
Of its 7 completed or terminated interventional studies of FDA-regulated products, 1 (14%) have results posted.
None of the studies under way reaches primary completion within a year.
Among the 46 studies in Breast Neoplasms by Samsung Medical Center, from their registry updates:
Nothing recorded among them since 2026-09-25.
This tab as a report to print or save as PDF → With an account.
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.
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.
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.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
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.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
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.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biopsy and archival tissue
A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.
Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Radiation: Adjuvant Breast Radiotherapy
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.
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.
Time frame: From study enrollment to 5 years
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.
Time frame: 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.
Time frame: 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
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: Baseline and up to 5 years after radiotherapy
Plan to share: 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.
No publications or documents are linked to this record.
Started Aug 2026 (actual). Primary completion is estimated for Aug 2036, 119 months after the start.
Of 1,191 non-industry observational studies under Breast Neoplasms, half reached primary completion within 58 months of starting (the median), counting those still running; a quarter within 25 and three quarters within 139. This study's planned 119 months is above that.
Counting every sponsor, half of 1,380 studies reached it within 55 months; a quarter within 25 and three quarters within 126.
How these figures are worked out, and which studies are left out of them.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
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