Study of Changes in Estrogen Levels and Grip Strength in Postmenopausal Women Who Have Received 4 to 6 Years of Hormone Therapy for Breast Cancer and Are Currently Receiving Letrozole on Clinical Trial IBCSG-35-07

An observational study of Breast Cancer, run by ETOP IBCSG Partners Foundation at 2 sites in 2 countries.

Completed

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

Trial summary

RATIONALE: Studying samples of blood in the laboratory from patients receiving treatment for cancer may help doctors learn more about changes that may occur in DNA and identify biomarkers related to cancer. Read more about this study

Who is it for?: Ages 18 to 120 years, women only
Conditions the study is for: Breast Cancer
What is being tested?: polymorphism analysis, laboratory biomarker analysis and quality-of-life assessment
Type of treatment: Surgery or procedure
How many people: 104 participants
Where: 2 sitesin 2 countries
Study dates: Jan 2011to 15 May 2019
Phase: Observational
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 18 to 120 years
Women only
No healthy volunteers
Adult, Older adult

Study population: Patients randomized to the SOLE trial (IBCSG 35-07) and participate in the Quality of Life substudy.

DISEASE CHARACTERISTICS:

Previously diagnosed with breast cancer
Endocrine-responsive, node-positive, resectable disease
Disease-free following 4-6 years of prior adjuvant endocrine therapy with selective estrogen-receptor modulators and/or aromatase inhibitors
Patient must be currently enrolled on clinical trial IBCSG-35-07 as well as the Quality-of-Life substudy
Hormone receptor status not specified

PATIENT CHARACTERISTICS:

Postmenopausal

PRIOR CONCURRENT THERAPY:

See Disease Characteristics

Trial locations and contacts

2 sites in 2 countries.

Country

City, postcode or hospital

2 sites in 2 countries

Australia1 site

Box Hill Hospital
Box Hill, Victoria, 3128

Other trials in Australia

Belgium1 site

CHU Liege - Domaine Universitaire du Sart Tilman
Liège, B-4000

Other trials in Belgium

About this study

Official title: SOLE Estrogen Substudy (SOLE-EST) - Investigating Changes in Estrogen Levels and Grip Strength for Patients Participating in the SOLE Trial

PURPOSE: This clinical trial is studying changes in estrogen levels and grip strength in postmenopausal women who have received 4 to 6 years of hormone therapy for breast cancer and are currently receiving letrozole on clinical trial IBCSG-35-07.

Read the detailed description

OBJECTIVES:

Primary

To determine the serum level of estrogens (Estradiol [E2], Estrone [E1], and Estrone Sulphate [E1S] and sex hormone binding globulin [SHBG]) in postmenopausal women with prior endocrine-responsive, node-positive, resectable breast cancer completing 4 to 6 years of adjuvant endocrine therapy and enrolled on clinical trial IBCSG-35-07 receiving letrozole.
To determine the degree of recovery of E2, E1, and E1S during the 3-month letrozole-off gap.

Secondary

To determine the association between estrogen level changes and the clinical outcomes of toxicity and quality of life.
To determine the effect of prior adjuvant endocrine therapy, age, body mass index, and type of menopause on estrogen levels.
To determine the variability of estrogen level changes and its association with germline single nucleotide polymorphisms.
To examine changes in grip-strength score.

OUTLINE: This is a multicenter study.

All patients undergo blood sample collection at baseline for the analysis of single nucleotide polymorphisms, after randomization on clinical trial IBCSG-35-07 and prior to the beginning treatment on IBCSG-35-07. Patients also undergo serum collection at baseline and at 9, 10.5, and 12 months for the analysis of estrogen levels and sex hormone binding globulins. Patients undergo measurement of grip strength at baseline and at 9 and 12 months. Samples may be banked for future research studies.

Patients complete quality-of-life questionnaires (Breast Cancer Prevention Trial [BCPT] Symptom Scales on Form 35-PRS and IBCSG Trial 35-07 QL Form) periodically.

Conditions: Breast Cancer
Being tested: polymorphism analysis, laboratory biomarker analysis, quality-of-life assessment
Keywords: stage IA breast cancer, stage IB breast cancer, stage II breast cancer, stage IIIA breast cancer
Medical subject headings: Breast Neoplasms

What participants receive

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

polymorphism analysisGenetic
SNPs will be genotyped in whole blood samples taken at baseline.
laboratory biomarker analysisOther
Biomarkers will be assessed in blood and serum samples at different time points.
quality-of-life assessmentProcedure or surgery
Quality of life will be assessed using the Breast Cancer Prevention Trial (BCPT) Symptom Scales and the IBCSG Trial 35-07 QL Form.

What is being measured

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

Levels of Estrone (E1), Estradiol (E2), and Estrone Sulphate (E1S) Among Patients in the Longitudinal Analysis Population
In SOLE-EST, levels of E1, E2, and E1S were summarized over time at 0 (baseline), 9, 10.5, and 12 months from randomization among patients in the longitudinal analysis population (N=90 with post-baseline sample).
Measured: 0 (baseline), 9, 10.5, and 12 months from randomization
Percent Change of E1, E2, and E1S Levels at 9, 10.5, and 12 Months From Baseline, by Treatment Group
Changes in hormone levels (E1, E2, and E1S levels), as percentage change over time according to treatment assignment (at 9, 10.5 and 12 months from baseline).
Measured: 9, 10.5, and 12 months from baseline

Secondary outcomes (3)

Toxicity Grade Changes for Arthralgia, Hot Flushes, and Insomnia
Toxicity grade changes from 6 to 12 months (hot flashes, insomnia and arthralgia; Common Terminology Criteria for Adverse Events (CTCAE) version 3 values 1- 4 grouped as no change, increase in grade [worsening] or decrease in grade [improvement])
Measured: 6 and 12 months
Quality of Life (QoL) Score Changes
All patients in SOLE-EST were assessed for symptom specific QoL. QoL changes from 6 to 12 months (sleep change, hot flushes, tiredness, difficulties of becoming aroused, loss of sexual interest, physical wellbeing and mood; LASA (linear analogue self-assessment) scores 0-100 (higher is better QoL) were calculated as 12 months minus 6 months, so that negative is worsening and positive is improvement.
Measured: 6 and 12 months: Change is calculated from 12 months minus 6 months, therefore positive values indicate an improved condition and negative values indicate a declined condition
Change in Grip-strength Score in the Dominant Hand
Grip strength was measured using the Martin Vigorimeter (a modified sphygmomanometer which measures the force of compression in kilo pascal by means of a compressible rubber ball). To perform the hand grip test, the patients were asked to squeeze the ball of a modified sphygmomanometer three times with maximal force and the maximal value of three trials of each hand were used for evaluation. Higher value represents greater strength, thus changes are calculated as 12 months minus 9 months so that positive is improved condition and negative is declined condition.
Measured: Changes in grip strength score is calculated at 12 months minus 9 months

Timeline

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

Jan 201115 May 2019

First posted21 Jan 2011 (estimated)
Study startJan 2011
Primary completion15 May 2019
Study completion15 May 2019

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: Observational
Observational model: Cohort
Time perspective: Prospective
Enrolment: 104 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT01281137
Sponsor's protocol ID: CDR0000692740
Other IDs: IBCSG-35-07-SUBSTUDY, BIG-1-07-SUBSTUDY, 2007-001370-88, EU-21101
Acronym: SOLE-EST
Status last verified: Sep 2021
First submitted: 20 Jan 2011
Last updated: 6 Oct 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes

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?

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Study at a glance

From the registry record, last updated by the sponsor on 6 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: SOLE Estrogen Substudy (SOLE-EST) - Investigating Changes in Estrogen Levels and Grip Strength for Patients Participating in the SOLE Trial
ClinicalTrials.gov ID: NCT01281137
Acronym / sponsor ID: SOLE-EST / CDR0000692740
Conditions: Breast Cancer
Keywords: stage IA breast cancer, stage IB breast cancer, stage II breast cancer, stage IIIA breast cancer
Study type: Observational
Recruitment status: Completed
Enrolment: 104 participants (actual)
Lead sponsor: ETOP IBCSG Partners FoundationResearch network
Study start: Jan 2011 (actual)
Primary completion: 15 May 2019 (actual)
Study completion: 15 May 2019 (actual)
First posted: 21 Jan 2011 (estimated)
Results: Posted 6 Oct 2021

Clinical summary

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

Detailed description

OBJECTIVES:

Primary

To determine the serum level of estrogens (Estradiol [E2], Estrone [E1], and Estrone Sulphate [E1S] and sex hormone binding globulin [SHBG]) in postmenopausal women with prior endocrine-responsive, node-positive, resectable breast cancer completing 4 to 6 years of adjuvant endocrine therapy and enrolled on clinical trial IBCSG-35-07 receiving letrozole.
To determine the degree of recovery of E2, E1, and E1S during the 3-month letrozole-off gap.

Secondary

To determine the association between estrogen level changes and the clinical outcomes of toxicity and quality of life.
To determine the effect of prior adjuvant endocrine therapy, age, body mass index, and type of menopause on estrogen levels.
To determine the variability of estrogen level changes and its association with germline single nucleotide polymorphisms.
To examine changes in grip-strength score.

OUTLINE: This is a multicenter study.

Patients complete quality-of-life questionnaires (Breast Cancer Prevention Trial [BCPT] Symptom Scales on Form 35-PRS and IBCSG Trial 35-07 QL Form) periodically.

Study design

Observational model: Cohort
Time perspective: Prospective

Who may qualify

Ages: 18 to 120 years
Sex: Female only
Healthy volunteers: Not accepted
Age groups: Adult, Older adult
Study population: Patients randomized to the SOLE trial (IBCSG 35-07) and participate in the Quality of Life substudy.

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
polymorphism analysisSNPs will be genotyped in whole blood samples taken at baseline.	Genetic	–
laboratory biomarker analysisBiomarkers will be assessed in blood and serum samples at different time points.	Other	–
quality-of-life assessmentQuality of life will be assessed using the Breast Cancer Prevention Trial (BCPT) Symptom Scales and the IBCSG Trial 35-07 QL Form.	Procedure or surgery	–

Primary outcome

Levels of Estrone (E1), Estradiol (E2), and Estrone Sulphate (E1S) Among Patients in the Longitudinal Analysis Population
Time frame: 0 (baseline), 9, 10.5, and 12 months from randomization
In SOLE-EST, levels of E1, E2, and E1S were summarized over time at 0 (baseline), 9, 10.5, and 12 months from randomization among patients in the longitudinal analysis population (N=90 with post-baseline sample).
Percent Change of E1, E2, and E1S Levels at 9, 10.5, and 12 Months From Baseline, by Treatment Group
Time frame: 9, 10.5, and 12 months from baseline
Changes in hormone levels (E1, E2, and E1S levels), as percentage change over time according to treatment assignment (at 9, 10.5 and 12 months from baseline).

3 secondary outcomes

Toxicity Grade Changes for Arthralgia, Hot Flushes, and Insomnia
Time frame: 6 and 12 months
Quality of Life (QoL) Score Changes
Time frame: 6 and 12 months: Change is calculated from 12 months minus 6 months, therefore positive values indicate an improved condition and negative values indicate a declined condition
Change in Grip-strength Score in the Dominant Hand
Time frame: Changes in grip strength score is calculated at 12 months minus 9 months

Results and safety

Results posted to the registry on 6 Oct 2021, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Continuous Letrozole Treatment Group	25	25
Intermittent Letrozole Treatment Group	79	78

Primary outcome: Levels of Estrone (E1), Estradiol (E2), and Estrone Sulphate (E1S) Among Patients in the Longitudinal Analysis Population

Time frame: 0 (baseline), 9, 10.5, and 12 months from randomization. Median (Inter-Quartile Range). Unit: pg/mL

Measure	Continuous Letrozole Treatment Group (Baseline, Month 0) n = 21	Intermittent Letrozole Treatment Group (Baseline, Month 0) n = 69	Continuous Letrozole Treatment Group (9 Months) n = 21	Intermittent Letrozole Treatment Group (9 Months) n = 64	Continuous Letrozole Treatment Group (10.5 Months) n = 20	Intermittent Letrozole Treatment Group (10.5 Months) n = 64	Continuous Letrozole Treatment Group (12 Months) n = 19	Intermittent Letrozole Treatment Group (12 Months) n = 62
E1	12.4 (9.7 to 23.4)	14.3 (5.8 to 26.1)	4.8 (4.2 to 5.5)	5.1 (4.3 to 5.8)	4.7 (3.9 to 5.5)	21.6 (15.4 to 29.7)	5.1 (4.4 to 7.0)	26.8 (18.5 to 35.7)
E2	4.6 (3.3 to 7.3)	4.7 (3.4 to 6.9)	2.6 (2.2 to 4.0)	3.2 (2.4 to 4.0)	2.6 (2.0 to 3.7)	6.7 (4.8 to 8.7)	2.9 (2.3 to 4.0)	7.3 (5.4 to 10.5)
E1S	90.7 (75.2 to 150.2)	87.6 (58.1 to 142.3)	61.1 (50.5 to 76.2)	54.1 (47.8 to 63.0)	57.1 (50.6 to 69.0)	128.6 (90.7 to 156.8)	59.1 (47.3 to 73.5)	125.1 (93.0 to 188.2)

Population analysed: Longitudinal analysis group: There were 90/103 patients (21 continuous, 69 intermittent) who had baseline and one or more samples at 9, 10.5 and/or 12 months and could be included in analyses of hormone levels over time. At 9, 10.5, and 12 months, 85, 84, and 81, respectively, could be included in analyses of hormone levels over time.

Primary outcome: Percent Change of E1, E2, and E1S Levels at 9, 10.5, and 12 Months From Baseline, by Treatment Group

Time frame: 9, 10.5, and 12 months from baseline. Median (Inter-Quartile Range). Unit: percentage change

Measure	Continuous Letrozole Treamtnet Group (9 Months) n = 21	Intermittent Letrozole Treatment Group (9 Months) n = 64	Continuous Letrozole Treatment Arm (10.5 Months) n = 20	Intermittent Letrozole Treatment Group (10.5 Months) n = 64	Continuous Letrozole Treatment Arm (12 Months) n = 19	Intermittent Letrozole Treatment Group (12 Months) n = 62
Percent change of E1	-58.2 (-77.2 to -44.9)	-59.3 (-79.4 to -13.9)	-67.3 (-81.1 to -53.0)	76.6 (-22.7 to 289.3)	-57.8 (-75.4 to -34.8)	68.7 (-14.4 to 318.9)
Percent change of E2	-34.2 (-59.2 to -10.6)	-32.2 (-58.9 to -2.8)	-39.6 (-56.9 to -11.1)	62.7 (-18.1 to 111.3)	-47.7 (-60.5 to 0.2)	46.2 (-12.1 to 118.3)
Percent change of ES1	-29.8 (-60.9 to -15.3)	-42.3 (-62.2 to -7.9)	-38.7 (-63.4 to -22.6)	32.9 (-20.3 to 96.7)	-36.7 (-68.5 to -21.5)	31.6 (-2.4 to 103.1)

Population analysed: Longitudinal Analysis Population: There were 90/103 patients (21 continuous, 69 intermittent) who had baseline and one or more samples at 9, 10.5 and/or 12 months and could be included in analyses of hormone levels over time. 90 patients at baseline, 85 patients at month 9, 84 patients at month 10.5, and 81 patients at month 12.

3 secondary outcomes are reported in the full results.

Adverse events

Time frame: Adverse event (AE) information were collected at baseline and at 6 and 12 months in the SOLE main study.. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Continuous Letrozole Treatment Group	0 of 25 (0%)	0 of 25 (0%)	0 of 25
Intermittent Letrozole Treatment Group	0 of 78 (0%)	0 of 78 (0%)	0 of 78

Limitations and caveats (from the sponsor): After 5 years of adjuvant endocrine therapy, resistant tumoral cells could be different from those present at initial diagnosis, and the apoptotic effect of estrogen on these cells might be insufficient. It is possible that the intermittent treatment was given too late.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 6 Oct 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.

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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.

Jacquie Chirgwin, MD study chair

Box Hill Hospital

Guy Jerusalem, MD, PhD study chair

CHU Liege - Domaine Universitaire du Sart Tilman

2 sites in 2 countries: see every site and its status.

Questions about this trial

What is this clinical trial studying?

An observational study of Breast Cancer, run by ETOP IBCSG Partners Foundation at 2 sites in 2 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

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 6 Oct 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 Australia, Belgium. 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. 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?

Yes. Results are posted in the registry (first posted 6 Oct 2021). 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?

Levels of Estrone (E1), Estradiol (E2), and Estrone Sulphate (E1S) Among Patients in the Longitudinal Analysis Population (time frame: 0 (baseline), 9, 10.5, and 12 months from randomization). The study lists 2 primary outcomes in all. 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 NCT01281137.

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 6 Oct 2026.