Sulindac and Breast Density in Women at Risk of Developing Breast Cancer

A Phase 2 study testing Sulindac Pill in people with Breast Cancer, run by Alison Stopeck at 2 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Trial summary

The primary objective of this study is to determine if sulindac at a dose of 150 mg twice a day for 12 months reduces breast density in postmenopausal women at elevated risk of breast cancer when compared to a placebo control. Read more about this study

Who is it for?: Ages 35 to 70 years, women only
Conditions the study is for: Breast Cancer
What is being tested?: Sulindac Pill
Type of treatment: Pill or oral medicine
Could I receive a placebo?: Yes, some participants may receive a placebo
How many people: 61 participants
Where: 2 sitesUnited States
Study dates: 20 Nov 2020to 19 May 2025
Phase: Phase 2
Are there results?: Yes, posted in the registrySummary in the doctors' view

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 35 to 70 years
Women only
No healthy volunteers
Adult, Older adult

Who may be able to join

Age ≤70 years
Subject must be postmenopausal.
Must have at least one healthy normal appearing breast (no prior diagnosis of invasive cancer, radiation or prosthetics). Prior biopsies are acceptable.
Must have dense breasts
Must be at elevated risk for developing breast cancer by abnormal pathological findings, family history, or genetic predisposition
A negative fecal occult blood test
Normal organ function
Hormonal therapy with aromatase inhibitors is allowed

Who cannot join

Daily aspirin or other daily anti inflammatory use.
Known intolerance to anti inflammatory.
Use of any selective estrogen receptor modulator therapy (e.g., tamoxifen, raloxifene) within past 12 months
Gastrointestinal, bleeding or coagulation, cardiovascular disorders.
Diabetes requiring insulin therapy.
Current regular smoker.

Show all 9Show fewer

History of claustrophobia or inability to undergo imaging in a closed magnetic resonance imaging.
Cardiac pacemaker, cochlear implants, magnetic surgical clips or prostheses that would preclude MRI.
Uncontrolled hypertension.

Trial locations and contacts

2 sites in 1 country.

United States2 sites

Cedars Sinai - Cancer
Los Angeles, California, 90048
Stony Brook University Cancer Center
Stony Brook, New York, 11794

Other trials in United States

About this study

Official title: Double-blind, Randomized Phase II Clinical Trial of Sulindac for Reducing Breast Density in Postmenopausal Women at Risk of Developing Breast Cancer

Conditions: Breast Cancer
Being tested: Sulindac Pill, Placebo
Keywords: Breast Density
Medical subject headings: Breast Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Sulindac PillDrug
Randomized participants will receive either 150 mg oral sulindac twice daily.
PlaceboDrug
placebo pills twice daily

Study groups in NCT04542135
Study group	Role	What they receive
Sulindac	Active comparator	sulindac 150 mg Receives: Drug: Sulindac Pill
Placebo	Placebo comparator	placebo pill Receives: Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

Change in Percent Breast Density by MRI Between Treatment Arms
The primary objective of this study is to determine if sulindac at a dose of 150 mg BID for 12 months reduces breast density in postmenopausal women at elevated risk of breast cancer when compared to a placebo control. The dependent variable is the relative change in percent breast density. Percent breast density is the estimated percentage of breast volume that appears dense versus fatty on the MRI, and relative change is calculated as the difference between the follow-up and baseline values divided by the baseline value.
Measured: 12 months

Secondary outcomes (2)

Change in Percent Breast Density by MRI Between Treatment Arms
The secondary objective of this study is to determine if sulindac at a dose of 150 mg BID for 6 months reduces breast density in postmenopausal women at elevated risk of breast cancer when compared to a placebo control. The dependent variable is the relative change in percent breast density. Percent breast density is the estimated percentage of breast volume that appears dense versus fatty on the MRI, and relative change is calculated as the difference between the follow-up and baseline values divided by the baseline value.
Measured: 6 months
Changes in Percent Breast Density by MRI Within and Between Treatment Arms, Stratified by Use of Aromatase Inhibitors
The secondary objective is to determine if sulindac at a dose of 150 mg BID for 12 months reduces breast density in postmenopausal women at elevated risk of breast cancer when compared to a placebo control, with analyses stratified by aromatase inhibitor (AI) use. Results are reported separately for participants on AI therapy and those not on AI therapy.
Measured: 12 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

20 Nov 202019 May 2025

First posted9 Sep 2020
Study start20 Nov 2020
Primary completion22 Apr 2025
Study completion19 May 2025

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
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 2
Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Masking: Single blind
Who is masked: Investigator
Enrolment: 61 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT04542135
Sponsor's protocol ID: STOP-BC Trial
Status last verified: Apr 2025
First submitted: 27 Aug 2020
Last updated: 17 Jul 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: No: There is no plan to share individual participant data to non study related researchers.

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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All Breast Cancer trials

Study at a glance

From the registry record, last updated by the sponsor on 17 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Double-blind, Randomized Phase II Clinical Trial of Sulindac for Reducing Breast Density in Postmenopausal Women at Risk of Developing Breast Cancer
ClinicalTrials.gov ID: NCT04542135
Acronym / sponsor ID: STOP-BC Trial
Conditions: Breast Cancer
Keywords: Breast Density
Phase: Phase 2
Study type: Interventional
Recruitment status: Completed
Enrolment: 61 participants (actual)
Lead sponsor: Alison StopeckUniversity, hospital or other
Collaborators: Medical University of South Carolina, Cedars-Sinai Medical Center
Study start: 20 Nov 2020 (actual)
Primary completion: 22 Apr 2025 (actual)
Study completion: 19 May 2025 (actual)
First posted: 9 Sep 2020 (actual)
Results: Posted 17 Jul 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Study design

Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Masking: Single blind (investigator)
Number of arms: 2

Arm	Type	Receives
Sulindac	Active comparator	Drug: Sulindac Pillsulindac 150 mg
Placebo	Placebo comparator	Drug: Placeboplacebo pill

Who may qualify

Ages: 35 to 70 years
Sex: Female only
Healthy volunteers: Not accepted
Age groups: Adult, Older adult

Key inclusion criteria (8 listed)

Age ≤70 years
Subject must be postmenopausal.
Must have at least one healthy normal appearing breast (no prior diagnosis of invasive cancer, radiation or prosthetics). Prior biopsies are acceptable.
Must have dense breasts
Must be at elevated risk for developing breast cancer by abnormal pathological findings, family history, or genetic predisposition

Key exclusion criteria (9 listed)

Daily aspirin or other daily anti inflammatory use.
Known intolerance to anti inflammatory.
Use of any selective estrogen receptor modulator therapy (e.g., tamoxifen, raloxifene) within past 12 months
Gastrointestinal, bleeding or coagulation, cardiovascular disorders.
Diabetes requiring insulin therapy.

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
Sulindac PillRandomized participants will receive either 150 mg oral sulindac twice daily.	Drug	Sulindac
Placeboplacebo pills twice daily	Drug	Placebo

Primary outcome

Change in Percent Breast Density by MRI Between Treatment Arms
Time frame: 12 months
The primary objective of this study is to determine if sulindac at a dose of 150 mg BID for 12 months reduces breast density in postmenopausal women at elevated risk of breast cancer when compared to a placebo control. The dependent variable is the relative change in percent breast density. Percent breast density is the estimated percentage of breast volume that appears dense versus fatty on the MRI, and relative change is calculated as the difference between the follow-up and baseline values divided by the baseline value.

2 secondary outcomes

Change in Percent Breast Density by MRI Between Treatment Arms
Time frame: 6 months
Changes in Percent Breast Density by MRI Within and Between Treatment Arms, Stratified by Use of Aromatase Inhibitors
Time frame: 12 months

Results and safety

Results posted to the registry on 17 Jul 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Sulindac	31	25
Placebo	30	20

Primary outcome: Change in Percent Breast Density by MRI Between Treatment Arms

Time frame: 12 months. Least squares mean (95% Confidence Interval). Unit: Relative change (%) of percent density

Measure	Sulindac n = 28	Placebo n = 26
Value	-4.85 (-11.29 to 1.59)	-6.29 (-13.36 to 0.78)

Sulindac vs Placebo: Mean Difference (Final Values): 1.44 (95% CI -6.23 to 9.11), p = 0.7060, Mixed Models Analysis

Population analysed: Linear mixed effect model for longitudinal data is used for testing the relative change in percent breast density. Participants who completed 6 months in the study and for whom percent breast density data were available were included in analysis of primary outcome.

2 secondary outcomes are reported in the full results.

Adverse events

Time frame: from enrollment until end of follow-up, up to 13 months. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Sulindac	1 of 31 (3.2%)	27 of 31 (87.1%)	0 of 31
Placebo	1 of 30 (3.3%)	22 of 30 (73.3%)	0 of 30

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 17 Jul 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Individual participant dataSharing planned: No. There is no plan to share individual participant data to non study related researchers.

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Not yet recruitingObservational study
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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.

Alison S Stopeck, MD principal investigator

Stony Brook University

Patricia A Thompson-Carino, PhD principal investigator

University of Arizona

2 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Sulindac Pill in people with Breast Cancer, run by Alison Stopeck at 2 sites in United States.

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 8 inclusion and 9 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 17 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 2 sites in United States. 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.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 17 Jul 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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 Percent Breast Density by MRI Between Treatment Arms (time frame: 12 months). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04542135.

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 17 Jul 2026.