Breast CancerNCT07145827
Effect of Metformin on Endometrial Thickness in Postmenopausal Breast Cancer Patients Receiving Tamoxifen
A study testing Metfomin and tamoxifen in people with Breast Cancer and Endometrial Hyperplasia and Endometrial Cancers, run by Uruk University at 1 site in Iraq.
Trial summary
The goal of this clinical trial is to learn if metformin can reduce the increase in endometrial thickness caused by tamoxifen in women with estrogen-positive breast cancer taking tamoxifen for more than 1 year. It will also learn about the safety of taking metformin with tamoxifen. Read more about this study
- Who is it for?
- Any age, women only
- Conditions the study is for
- Breast Cancer, Endometrial Hyperplasia and Endometrial Cancers
- What is being tested?
- Metfomin and tamoxifen
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 60 participants
- Where
- 1 siteIraq
- Study dates
- 2 Jan 2024to 1 Jul 2025
- Phase
- Interventional
- 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 Any age
- Women only
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Postmenopausal Female patients (amenorrhea ≥ 12 months).
- Histologically proven (Estrogen-positive) breast cancer.
- Completed all required surgery and/or chemotherapy (if indicated)
- On adjuvant tamoxifen for at least 1 year.
- Accepts to enroll in the study
Who cannot join
- Refusing to enroll in the study
- Ongoing or History of: endometrial or ovarian malignancy
- Concurrent hormonal therapy that might affect endometrial thickness
- Concurrent Diabetes mellitus in which metformin is prescribed.
- Known hypersensitivity or severe intolerance to metformin
Trial locations and contacts
1 site in 1 country.
Iraq1 site
Baghdad Medical City / Department of Oncology
Baghdad, Baghdad Governorate, 10045
About this study
The goal of this clinical trial is to learn if metformin can reduce the increase in endometrial thickness caused by tamoxifen in women with estrogen-positive breast cancer taking tamoxifen for more than 1 year. It will also learn about the safety of taking metformin with tamoxifen. The main questions it aims to answer are:
- Does metformin decrease endometrial thickness in women receiving tamoxifen?
- What medical problems do participants have when taking metformin with tamoxifen?
Read more
Researchers will compare tamoxifen plus metformin to tamoxifen plus placebo to see if metformin works to reduce endometrial thickness compared to placebo patients.
Participants will:
- Take metformin daily along with tamoxifen, or take tamoxifen with placebo.
- Acquire baseline assessment and then visit the clinic at 3 months, 6 months, 9 months and 12 months for checkups and trans abdominal ultrasound test for endometrial thickness, and to be monitored for any side effects or complications.
- Being tested
- Metfomin, tamoxifen, Placebo matching Metformin
- Keywords
- Metformin, Tamoxifen, Breast cancer, endometrial hyperplasia
- Medical subject headings
- Breast Neoplasms, Endometrial Hyperplasia, Endometrial Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
MetfominDrug
Metformin Tab. 500mg twice daily for 12 months (titrated to tolerance if needed).
tamoxifenDrug
Standard prescribed oncological dose.
Placebo matching MetforminDrug
An inert, film-coated tablet identical in appearance and packaging to metformin 500 mg (same size, shape, color, coating, weight, and dosing schedule), manufactured without active ingredient using standard excipients (e.g., microcrystalline cellulose, starch/croscarmellose, povidone, magnesium stearate) and identical film coat (e.g., hypromellose, polyethylene glycol, titanium dioxide). Packaged in sealed blisters to minimize odor/taste cues. Dispensed by the investigational pharmacy per randomization; to be taken twice daily"
| Study group | Role | What they receive |
|---|---|---|
| Tamoxifen + Metformin | Experimental | Participants in this arm (n=30) will continue taking the standard oncological tamoxifen dose as prescribed and receive an addition of metformin 500mg twice daily, titrated to tolerance, during the 12-month study period. Receives: Drug: Metfomin; Drug: tamoxifen |
| Tamoxifen + Placebo | Placebo comparator | Participants in this arm (n=30) will continue to receive the standard oncological dose of tamoxifen as prescribed, in addition to a placebo tablet matching the shape size and color of metformin tablet twice daily during the 12 months study period; they will act as the control group. Receives: Drug: tamoxifen; Drug: Placebo matching Metformin |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in endometrial thickness
Endometrial thickness will be measured using transabdominal ultrasound (in millimeters) by a trained radiologist. The primary outcome is the difference in endometrial thickness between the metformin plus tamoxifen group and the placebo plus tamoxifen control group.
Measured: Baseline, 3 months, 6 months, 9 months, and 12 months from enrollment
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Aug 2025
- Study start2 Jan 2024
- Primary completion1 Jul 2025
- Study completion1 Jul 2025
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 N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 60 participants (actual)
Sponsor and investigators
- Lead sponsor
- Uruk University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ghasak kais Abdulhussain, Uruk University
- Investigators
- Ghasak Kais Abdulhussain, BSc, MSc, PhD (Pharmacology), Principal investigator, Uruk University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07145827
- Sponsor's protocol ID
- UU-TAM-MET-2024-01
- Status last verified
- Sep 2025
- First submitted
- 18 Aug 2025
- Last updated
- 12 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: De-identified participant-level data, including endometrial thickness measurements, baseline demographics, and follow-up data relevant to primary outcomes.
Study at a glance
From the registry record, last updated by the sponsor on 12 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Metformin on Endometrial Thickness in Postmenopausal Breast Cancer Patients Receiving Tamoxifen
- ClinicalTrials.gov ID
- NCT07145827
- Acronym / sponsor ID
- UU-TAM-MET-2024-01
- Keywords
- Metformin, Tamoxifen, Breast cancer, endometrial hyperplasia
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 60 participants (actual)
- Lead sponsor
- Uruk UniversityUniversity, hospital or other
- Study start
- 2 Jan 2024 (actual)
- Primary completion
- 1 Jul 2025 (actual)
- Study completion
- 1 Jul 2025 (actual)
- First posted
- 28 Aug 2025 (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 goal of this clinical trial is to learn if metformin can reduce the increase in endometrial thickness caused by tamoxifen in women with estrogen-positive breast cancer taking tamoxifen for more than 1 year. It will also learn about the safety of taking metformin with tamoxifen. The main questions it aims to answer are:
- Does metformin decrease endometrial thickness in women receiving tamoxifen?
- What medical problems do participants have when taking metformin with tamoxifen?
Researchers will compare tamoxifen plus metformin to tamoxifen plus placebo to see if metformin works to reduce endometrial thickness compared to placebo patients.
Participants will:
- Take metformin daily along with tamoxifen, or take tamoxifen with placebo.
- Acquire baseline assessment and then visit the clinic at 3 months, 6 months, 9 months and 12 months for checkups and trans abdominal ultrasound test for endometrial thickness, and to be monitored for any side effects or complications.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Tamoxifen + Metformin | Experimental | Drug: Metfomin, Drug: tamoxifenParticipants in this arm (n=30) will continue taking the standard oncological tamoxifen dose as prescribed and receive an addition of metformin 500mg twice daily, titrated to tolerance, during the 12-month study period. |
| Tamoxifen + Placebo | Placebo comparator | Drug: tamoxifen, Drug: Placebo matching MetforminParticipants in this arm (n=30) will continue to receive the standard oncological dose of tamoxifen as prescribed, in addition to a placebo tablet matching the shape size and color of metformin tablet twice daily during the 12 months study period; they will act as the control group. |
Who may qualify
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (5 listed)
- Postmenopausal Female patients (amenorrhea ≥ 12 months).
- Histologically proven (Estrogen-positive) breast cancer.
- Completed all required surgery and/or chemotherapy (if indicated)
- On adjuvant tamoxifen for at least 1 year.
- Accepts to enroll in the study
Key exclusion criteria (5 listed)
- Refusing to enroll in the study
- Ongoing or History of: endometrial or ovarian malignancy
- Concurrent hormonal therapy that might affect endometrial thickness
- Concurrent Diabetes mellitus in which metformin is prescribed.
- Known hypersensitivity or severe intolerance to metformin
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 |
|---|---|---|
| MetfominMetformin Tab. 500mg twice daily for 12 months (titrated to tolerance if needed). | Drug | Tamoxifen + Metformin |
| tamoxifenStandard prescribed oncological dose. | Drug | Tamoxifen + Metformin, Tamoxifen + Placebo |
| Placebo matching MetforminAn inert, film-coated tablet identical in appearance and packaging to metformin 500 mg (same size, shape, color, coating, weight, and dosing schedule), manufactured without active ingredient using standard excipients (e.g., microcrystalline cellulose, starch/croscarmellose, povidone, magnesium stearate) and identical film coat (e.g., hypromellose, polyethylene glycol, titanium dioxide). Packaged in sealed blisters to minimize odor/taste cues. Dispensed by the investigational pharmacy per randomization; to be taken twice daily" | Drug | Tamoxifen + Placebo |
Primary outcome
Change in endometrial thickness
Time frame: Baseline, 3 months, 6 months, 9 months, and 12 months from enrollment
Endometrial thickness will be measured using transabdominal ultrasound (in millimeters) by a trained radiologist. The primary outcome is the difference in endometrial thickness between the metformin plus tamoxifen group and the placebo plus tamoxifen control group.
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 12 Sep 2025.
- Individual participant dataSharing planned: Yes. De-identified participant-level data, including endometrial thickness measurements, baseline demographics, and follow-up data relevant to primary outcomes.
Related trials for Breast Cancer
Active, not recruiting
Streamlined Geriatric and Oncological Evaluation Based On IC Technology
Breast Cancer, Comorbidities and Coexisting Conditions
RecruitingPhase 2
Gene Signatures to Guide HR+MBC Therapy in a Diverse Cohort
Invasive Mammary Carcinoma, Metastatic Breast Cancer
Not yet recruitingObservational study
Comparison of Reliability, Time Cost, and Participant Comfort of Lymphedema Assessments in Upper Extremity
Lymphedema, Upper Extremity Lymphedema
RecruitingPhase 3
A Study of Camrelizumab Plus Chemotherapy in Combination With or Without Famitinib as Neoadjuvant Therapy in Participants With Triple Negative Breast Cancer (BCTOP-T-N01)
TNBC - Triple-Negative Breast Cancer
RecruitingPhase 3
Testing Whether Hormone Therapy With Ribociclib is as Effective as Chemotherapy Followed by Hormone Therapy With Ribociclib for the Treatment of High Anatomic Stage Breast Cancer With Low Recurrence Risk, The RxFINE-Low Trial
Anatomic Stage II Breast Cancer AJCC v8, Anatomic Stage IIIA Breast Cancer AJCC v8
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.
Ghasak Kais Abdulhussain, BSc, MSc, PhD (Pharmacology) principal investigator
Uruk University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Metfomin and tamoxifen in people with Breast Cancer and Endometrial Hyperplasia and Endometrial Cancers, run by Uruk University at 1 site in Iraq.
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 5 inclusion and 5 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 12 Sep 2025. 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 Iraq. 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. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
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?
Change in endometrial thickness (time frame: Baseline, 3 months, 6 months, 9 months, and 12 months from enrollment). 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 12 Sep 2025.