Clinical trial · Interventional
Effect of Metformin on Endometrial Thickness in Postmenopausal Breast Cancer Patients Receiving Tamoxifen
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Summary
Brief summary (as posted)
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: 1. Does metformin decrease endometrial thickness in women receiving tamoxifen? 2. 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: 1. Take metformin daily along with tamoxifen, or take tamoxifen with placebo. 2. 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.
Conditions
Conditions (2)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Breast Cancer | Malignant Breast Neoplasm | CURATED_EXACT | 0.92 |
| Endometrial Hyperplasia and Endometrial Cancers | — | UNRESOLVED | — |
Interventions
Interventions (3)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| Metfomin | Drug | — | UNRESOLVED |
| Placebo matching Metformin | Drug | — | UNRESOLVED |
| tamoxifen | Drug | Tamoxifen | ALIAS |
Design
Arms and outcomes
Arms (2)
- type
- EXPERIMENTAL
- label
- Tamoxifen + Metformin
- description
- 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.
- interventionNames
- Drug: Metfomin
- Drug: tamoxifen
- type
- PLACEBO_COMPARATOR
- label
- Tamoxifen + Placebo
- description
- 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.
- interventionNames
- Drug: tamoxifen
- Drug: Placebo matching Metformin
Primary outcomes (1)
Eligibility
Eligibility (as posted)
- Sex
- Female
Show eligibility criteria text
Inclusion Criteria: * 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 Exclusion Criteria: * 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
References
Publications (0)
Data not yet available