Tamoxifen preventive study

The efficacy of tamoxifen to prevent the incidence of breast cancer in Japanese women with pathogenic mutations of BRCA2

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

JPRN

Registry ID

JPRN-jRCTs031200222

Enrollment

210

Registered

2020-11-30

Start date

2021-01-26

Completion date

Unknown

Last updated

2026-06-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Breast cancer breast cancer, BRCA2, tamoxifen, prevention

Interventions

administration of tamoxifen

Eligibility

Sex/Gender

Female

Inclusion criteria

Inclusion criteria: 1)Women of age >= 20 and <=70 years at enrollment 2)Women with a confirmed deleterious BRCA2 germline mutation 3)No evidence of breast cancer by mammography and breast ultrasound with latest examination prior to enrollment 4)ECOG performance status (PS) is 0 or 1 5)Women who do not wish or plan for preventive mastectomy 6)Women who have major organ functions 7)Women who have written informed consent to participate in this study Genetic tests tested outside of Japan will be those that meet CLIA criteria.

Exclusion criteria

Exclusion criteria: 1)Women who underwent bilateral mastectomy 2)History of invasive breast cancer or non-invasive ductal carcinoma 3)History of invasive cancer except for basal cell carcinoma, spinous cell carcinoma, carcinoma in situ of the cervix, papilla cancer or follicular cancer 4)Any medical or psychiatric condition that may prevent the subject from completing the study 5)Women who are judged inappropriate to participate the study by the investigator

Design outcomes

Primary

Measure	Time frame
The incidence of breast cancer in women with BRCA2 deleterious mutation after three years of low dose tamoxifen treatment (overall/ER-positive breast cancer)	—

Secondary

Measure	Time frame
1) The incidence of non-invasive ductal carcinoma in women with BRCA2 deleterious mutation after three years of low dose tamoxifen treatment(overall/ER-positive ductal carcinoma) 2)Evaluation of tolerability of tamoxifen (incidence of endometrial cancer/ovarian cancer/thrombus/fracture/cardiovascular event) 3) Adverse events and side effects 4) Diagnosis accuracy of breast MRI (BI-RADS(R) category determination) 5) Sensitivity of breast MRI to breast cancer detection 6) Frequency and percentage of malignancy of MRI guided biopsy 7) Relationship between the degree of background parenchymal enhancement (BPE) by breast MRI and the incidence of breast cancer 8) Sensitivity of miRNA and ctDNA to breast cancer detection	—

Measure

Time frame

1) The incidence of non-invasive ductal carcinoma in women with BRCA2 deleterious mutation after three years of low dose tamoxifen treatment(overall/ER-positive ductal carcinoma) 2)Evaluation of tolerability of tamoxifen (incidence of endometrial cancer/ovarian cancer/thrombus/fracture/cardiovascular event) 3) Adverse events and side effects 4) Diagnosis accuracy of breast MRI (BI-RADS(R) category determination) 5) Sensitivity of breast MRI to breast cancer detection 6) Frequency and percentage of malignancy of MRI guided biopsy 7) Relationship between the degree of background parenchymal enhancement (BPE) by breast MRI and the incidence of breast cancer 8) Sensitivity of miRNA and ctDNA to breast cancer detection

—

Contacts

Public ContactKanae Taruno

SHOWA Medical University Hospital

ktaruno@med.showa-u.ac.jp+81-3-3784-8000

Outcome results

None listed

Source: JPRN (via WHO ICTRP) · Data processed: Jul 3, 2026