Trial · NCT00553410

Letrozole in Preventing Cancer in Postmenopausal Women Who Have Received 4-6 Years of Hormone Therapy for Hormone Receptor-Positive, Lymph Node-Positive, Early-Stage Breast Cancer

NCT00553410, Phase 3, Completed, ETOP IBCSG Partners Foundation; results first posted 2019-01-29

3 sourcestrials-2026-11-12-0.5.0

Cite this record

ConductScience Library. Letrozole in Preventing Cancer in Postmenopausal Women Who Have Received 4-6 Years of Hormone Therapy for Hormone Receptor-Positive, Lymph Node-Positive, Early-Stage Breast Cancer. Trials, record NCT00553410. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT00553410

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Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: Letrozole in Preventing Cancer in Postmenopausal Women Who Have Received 4-6 Years of Hormone Therapy for Hormone Receptor-Positive, Lymph Node-Positive, Early-Stage Breast Cancer
NCT number: NCT00553410
Status: Completed
Phases: Phase 3
Enrollment: 4,884 participants, actual
Lead sponsor: ETOP IBCSG Partners Foundation
Conditions: Breast Cancer
Interventions: Letrozole, Letrozole
First posted: 2007-11-05
Last updated: 2026-10-23
Other registries' IDs: eudract:2007-001370-88
Results first posted: 2019-01-29

Source ClinicalTrials.gov

Registered outcomes4

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	Disease-free Survival (DFS)	5-year estimates, reported at a median follow-up of 60 months	Duration of time from randomization to the first indication of the following events: invasive recurrence at local (including recurrence restricted to the breast after breast conserving treatment), regional or distant sites; a new invasive cancer in the contralateral breast; any second (non-breast) invasive malignancy; or a death without prior cancer event. Appearance of DCIS or LCIS either in the ipsilateral or in the contralateral breast was not be considered as an event for DFS. In the absence of an event, DFS was censored at the date of last follow-up visit.
Secondary	Overall Survival	5-year estimates, reported at a median follow-up of 60 months	Duration of time from randomization to death from any cause, or was censored at the date last known alive. (Note, for patients who withdrew consent or were lost to follow-up but follow-up for survival was possible through hospital or registry records, OS was censored at the date last known alive rather than date of last follow-up/withdrawn consent).
Secondary	Distant Recurrence-free Interval (DRFI)	5-year estimates, reported at a median follow-up of 60 months	Duration of time from randomization to the first indication of invasive breast recurrence at a distant site. In the absence of an event, DRFI was censored at the date of last follow-up visit or date or death without distant recurrence.\* \*This endpoint replaced DDFS, which was specified in the protocol
Secondary	Breast Cancer-free Interval	5-year estimates, reported at a median follow-up of 60 months	Duration of time from randomization to the first indication of the following events: invasive breast recurrence at local, regional or distant sites; a new invasive cancer in the contralateral breast (second non-breast malignancies are ignored). In the absence of an event, BCFI was censored at the date of last follow-up visit or date of death without prior breast cancer event.

Source ClinicalTrials.gov

Outcomes4

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	Disease-free Survival (DFS)	5-year estimates, reported at a median follow-up of 60 months	Intention-to-treat	percentage of patients	NUMBER
SECONDARY	Overall Survival	5-year estimates, reported at a median follow-up of 60 months	Intention-to-treat	percentage of patients	NUMBER
SECONDARY	Distant Recurrence-free Interval (DRFI)	5-year estimates, reported at a median follow-up of 60 months	Intention-to-treat	percentage of patients	NUMBER
SECONDARY	Breast Cancer-free Interval	5-year estimates, reported at a median follow-up of 60 months	Intention-to-treat	percentage of patients	NUMBER

Source ClinicalTrials.gov

Results by group8

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Value	Spread	Units
Disease-free Survival (DFS)	Arm A: Continuous Letrozole	87.5	95% Confidence Interval 86 to 88.8	percentage of patients
Disease-free Survival (DFS)	Arm B: Intermittent Letrozole	85.8	95% Confidence Interval 84.2 to 87.2	percentage of patients
Overall Survival	Arm A: Continuous Letrozole	93.7	95% Confidence Interval 92.6 to 94.7	percentage of patients
Overall Survival	Arm B: Intermittent Letrozole	94.3	95% Confidence Interval 93.2 to 95.2	percentage of patients
Distant Recurrence-free Interval (DRFI)	Arm A: Continuous Letrozole	92.5	95% Confidence Interval 91.3 to 93.5	percentage of patients
Distant Recurrence-free Interval (DRFI)	Arm B: Intermittent Letrozole	93.2	95% Confidence Interval 92 to 94.2	percentage of patients
Breast Cancer-free Interval	Arm A: Continuous Letrozole	91.2	95% Confidence Interval 89.9 to 92.3	percentage of patients
Breast Cancer-free Interval	Arm B: Intermittent Letrozole	90.9	95% Confidence Interval 89.6 to 92.1	percentage of patients

Source ClinicalTrials.gov

Participant flow6

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
Overall Study	STARTED	Arm A: Continuous Letrozole	2,441
Overall Study	STARTED	Arm B: Intermittent Letrozole	2,443
Overall Study	COMPLETED	Arm A: Continuous Letrozole	2,426
Overall Study	COMPLETED	Arm B: Intermittent Letrozole	2,425
Overall Study	NOT COMPLETED	Arm A: Continuous Letrozole	15
Overall Study	NOT COMPLETED	Arm B: Intermittent Letrozole	18

Source ClinicalTrials.gov

Adverse events450

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk
other	Cardiac-ischemia/infarction	Cardiac disorders	Arm A: Continuous Letrozole	15	2,411
other	Cardiac-ischemia/infarction	Cardiac disorders	Arm B: Intermittent Letrozole	23	2,417
other	Fatigue (asthenia, lethargy, malaise)	General disorders	Arm A: Continuous Letrozole	1,025	2,411
other	Fatigue (asthenia, lethargy, malaise)	General disorders	Arm B: Intermittent Letrozole	954	2,417
other	Fracture	Injury, poisoning and procedural complications	Arm A: Continuous Letrozole	148	2,411
other	Fracture	Injury, poisoning and procedural complications	Arm B: Intermittent Letrozole	136	2,417
other	Thrombosis/embolism (vascular access-related)	Injury, poisoning and procedural complications	Arm A: Continuous Letrozole	8	2,411
other	Thrombosis/embolism (vascular access-related)	Injury, poisoning and procedural complications	Arm B: Intermittent Letrozole	9	2,417
other	Osteoporosis	Musculoskeletal and connective tissue disorders	Arm A: Continuous Letrozole	1,113	2,411
other	Osteoporosis	Musculoskeletal and connective tissue disorders	Arm B: Intermittent Letrozole	1,119	2,417

1 to 10 of 450Source ClinicalTrials.gov

See all 450 adverse events

Adverse event totals6

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	Arm A: Continuous Letrozole	170	2,426
Total, all-cause mortality	Arm B: Intermittent Letrozole	146	2,425
Total, other adverse events	Arm A: Continuous Letrozole	2,257	2,411
Total, other adverse events	Arm B: Intermittent Letrozole	2,261	2,417
Total, serious adverse events	Arm A: Continuous Letrozole	1,004	2,411
Total, serious adverse events	Arm B: Intermittent Letrozole	1,052	2,417

Source ClinicalTrials.gov

Papers2

The papers the trial lists on ClinicalTrials.gov.

PMID	Listed as	Source
29158011	DERIVED	PubMed
33082214	DERIVED	PubMed

Grants0

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

None in this release.

Trial comparisons2

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

Comparison	Source
Arm A: Continuous Letrozole vs Arm B: Intermittent Letrozole: deaths from any cause	Trial comparisons
Arm A: Continuous Letrozole vs Arm B: Intermittent Letrozole: serious adverse events	Trial comparisons

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Data dates

The day each source was copied for this release.

ClinicalTrials.gov: 2026-11-12; ClinicalTrials.gov
Results, from AACT: 2026-03-23; AACT
NIH grant links: 2026-11-13; NIH RePORTER

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNo license stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

For software

Read this trial from software.

The record and each of its lists are JSON, twenty rows a page. No key.

GET https://conductscience.org/api/trials/v1/NCT00553410

GET https://conductscience.org/api/trials/v1/NCT00553410/events?page=2

API reference For AI assistants