UMIN-ICDS Clinical Trial
| Unique ID issued by UMIN | UMIN000063337 |
|---|---|
| Receipt number | R000072494 |
| Scientific Title | Observational Study on the Efficacy and Safety of Ultrahypofractionated Whole-Breast Irradiation after Breast-Conserving Surgery |
| Date of disclosure of the study information | 2026/11/16 |
| Last modified on | 2026/10/19 14:24:39 |
* This page includes information on clinical trials registered in UMIN clinical trial registed system.
* We don't aim to advertise certain products or treatments
Basic information
Public title
Observational Study on the Efficacy and Safety of Ultrahypofractionated Whole-Breast Irradiation after Breast-Conserving Surgery
Acronym
Observational Study of Ultrahypofractionated Whole-Breast Irradiation
Scientific Title
Observational Study on the Efficacy and Safety of Ultrahypofractionated Whole-Breast Irradiation after Breast-Conserving Surgery
Scientific Title:Acronym
Observational Study of Ultrahypofractionated Whole-Breast Irradiation
Region
| Japan |
Condition
Condition
Breast Cancer
Classification by specialty
| Radiology |
Classification by malignancy
Malignancy
Genomic information
NO
Objectives
Narrative objectives1
To prospectively investigate the outcomes of ultrahypofractionated whole-breast irradiation in patients following breast-conserving surgery and to clarify its efficacy and safety.
Basic objectives2
Safety,Efficacy
Basic objectives -Others
Trial characteristics_1
Trial characteristics_2
Developmental phase
Assessment
Primary outcomes
Proportion of adverse events occurrence
Key secondary outcomes
Base
Study type
Observational
Study design
Basic design
Randomization
Randomization unit
Blinding
Control
Stratification
Dynamic allocation
Institution consideration
Blocking
Concealment
Intervention
No. of arms
Purpose of intervention
Type of intervention
Interventions/Control_1
Interventions/Control_2
Interventions/Control_3
Interventions/Control_4
Interventions/Control_5
Interventions/Control_6
Interventions/Control_7
Interventions/Control_8
Interventions/Control_9
Interventions/Control_10
Eligibility
Age-lower limit
| 20 | years-old | <= |
Age-upper limit
| 80 | years-old | > |
Gender
Female
Key inclusion criteria
Patients with breast cancer who have undergone breast-conserving surgery at our institution and are deemed candidates for whole-breast irradiation without indication for postoperative regional nodal irradiation.
Key exclusion criteria
Patients currently undergoing treatment for another malignancy.
Target sample size
120
Research contact person
Name of lead principal investigator
| 1st name | Satoshi |
| Middle name | |
| Last name | Ishikura |
Organization
St. Luke's International University, St. Luke's International Hospital
Division name
Department of Radiation Oncology
Zip code
104-8560
Address
9-1 Akashi-cho, Chuo-ku, Tokyo, Japan
TEL
03-5550-7006
sishikur-ncche@umin.ac.jp
Public contact
Name of contact person
| 1st name | Satoshi |
| Middle name | |
| Last name | Ishikura |
Organization
St. Luke's International University, St. Luke's International Hospital
Division name
Department of Radiation Oncology
Zip code
104-8560
Address
9-1 Akashi-cho, Chuo-ku, Tokyo, Japan
TEL
03-5550-7006
Homepage URL
sishikur-ncche@umin.ac.jp
Sponsor or person
Institute
St. Luke's International University, St. Luke's International Hospital
Institute
Department
Personal name
Satoshi Ishikura
Funding Source
Organization
None
Organization
Division
Category of Funding Organization
Self funding
Nationality of Funding Organization
Other related organizations
Co-sponsor
Name of secondary funder(s)
IRB Contact (For public release)
Organization
Institutional Review Board of St. Luke's International University
Address
10-1 Akashi-cho, Chuo-ku, Tokyo, Japan
Tel
03-5550-2423
kenkyukikaku@luke.ac.jp
Secondary IDs
Secondary IDs
NO
Study ID_1
Org. issuing International ID_1
Study ID_2
Org. issuing International ID_2
IND to MHLW
Institutions
Institutions
Other administrative information
Date of disclosure of the study information
| 2026 | Year | 11 | Month | 16 | Day |
Related information
URL releasing protocol
Publication of results
Unpublished
Result
URL related to results and publications
Number of participants that the trial has enrolled
Results
Results date posted
Results Delayed
Results Delay Reason
Date of the first journal publication of results
Baseline Characteristics
Participant flow
Adverse events
Outcome measures
Plan to share IPD
IPD sharing Plan description
Progress
Recruitment status
Enrolling by invitation
Date of protocol fixation
| 2026 | Year | 10 | Month | 19 | Day |
Date of IRB
| 2026 | Year | 10 | Month | 19 | Day |
Anticipated trial start date
| 2026 | Year | 11 | Month | 16 | Day |
Last follow-up date
| 2031 | Year | 07 | Month | 31 | Day |
Date of closure to data entry
Date trial data considered complete
Date analysis concluded
Other
Other related information
Radiation therapy has been widely administered after breast conserving surgery to prevent local recurrence. Traditionally, whole breast moderate hypofractionation (42.56 Gy in 16 fractions), with an additional tumor bed boost (10-16 Gy in 4-8 fractions) for patients at higher risk of recurrence, has been the standard approach. However, the treatment course extends for at least three weeks, and the need for shorter treatment duration has long been recognized.
For selected low risk patients, accelerated treatment has become feasible through partial breast irradiation targeting the peritumoral region (30 Gy in 5 fractions). Even for patients still require whole breast irradiation, ultra-hypofractionated whole breast irradiation has attracted attention as an option that can reduce both treatment related toxicity and the burden of frequent hospital visits.
In the United Kingdom, where large randomized trials have been conducted, ultra-hypofractionated whole breast irradiation is already recommended in the consensus statement of The Royal College of Radiologists. Furthermore, the 2022 ESTRO recommendations and the NCCN Guidelines (2026 edition) list ultra hypofractionation as an accepted option for whole breast irradiation, and it has been widely adopted in Western countries. Although the 2026 edition of the Japanese Breast Cancer Clinical Practice Guidelines also includes this approach as a treatment option, its implementation in routine practice had been limited because reimbursement decreased substantially with fewer fractions.
Following the 2026 revision of the medical reimbursement system, the difference in reimbursement between ultra-hypofractionated and moderately hypofractionated whole breast irradiation has largely been eliminated, making clinical adoption more feasible. Nevertheless, evidence regarding its efficacy and safety in Japanese patients remains scarce.
This study evaluates the efficacy and safety of ultra-hypofractionated whole breast irradiation.
Management information
Registered date
| 2026 | Year | 10 | Month | 19 | Day |
Last modified on
| 2026 | Year | 10 | Month | 19 | Day |
Link to view the page
Value
https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000072494
